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SSC JE Mechanical Paper-I Practice Paper (2026 Exam Pattern, Solved Set)

SSC Junior Engineer (JE) • 2026 • 200 Questions • Free practice with solutions

Subjects included:Reasoning Ability (50)General Awareness (50)Mechanical Engineering (SSC JE) (100)
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Showing 200 Questions with Step-by-Step Solutions
Q1Reasoning Ability
Easy
Pen : Write :: Knife : ?
A. Steel
B. Kitchen
C. Sharp
D. Cut
View answer and explanation
Correct Option: D
A pen is used to write, and a knife is used to cut.
Q2Reasoning Ability
Easy
Doctor : Hospital :: Teacher : ?
A. Education
B. Book
C. School
D. Student
View answer and explanation
Correct Option: C
A doctor works in a hospital, and a teacher works in a school.
Q3Reasoning Ability
Easy
8 : 64 :: 9 : ?
A. 81
B. 72
C. 99
D. 18
View answer and explanation
Correct Option: A
The second number is the square of the first: 8² = 64, so 9² = 81.
Q4Reasoning Ability
Medium
CAT : ECV :: DOG : ?
A. FPI
B. FQI
C. GQJ
D. EPH
View answer and explanation
Correct Option: B
Each letter moves two places forward: C→E, A→C, T→V. So D→F, O→Q, G→I.
Q5Reasoning Ability
Easy
Bird : Nest :: Bee : ?
A. Honey
B. Flower
C. Sting
D. Hive
View answer and explanation
Correct Option: D
A bird lives in a nest and a bee lives in a hive.
Q6Reasoning Ability
Easy
5 : 125 :: 7 : ?
A. 294
B. 49
C. 245
D. 343
View answer and explanation
Correct Option: D
The second number is the cube of the first: 5³ = 125, so 7³ = 343.
Q7Reasoning Ability
Easy
Find the odd one out: Apple, Banana, Potato, Mango
A. Banana
B. Potato
C. Apple
D. Mango
View answer and explanation
Correct Option: B
Potato is a vegetable (a tuber), whereas the others are fruits.
Q8Reasoning Ability
Easy
Find the odd one out: 2, 3, 5, 9, 11
A. 11
B. 2
C. 5
D. 9
View answer and explanation
Correct Option: D
All the numbers except 9 are prime.
Q9Reasoning Ability
Medium
Find the odd letter pair: AC, EG, IK, MP
A. EG
B. MP
C. AC
D. IK
View answer and explanation
Correct Option: B
In AC, EG and IK the second letter is two places after the first. In MP the gap is three.
Q10Reasoning Ability
Easy
Find the odd one out: Mercury, Venus, Moon, Mars
A. Moon
B. Mercury
C. Mars
D. Venus
View answer and explanation
Correct Option: A
The Moon is a satellite, while the others are planets.
Q11Reasoning Ability
Easy
Find the odd one out: Square, Rectangle, Triangle, Rhombus
A. Rhombus
B. Triangle
C. Rectangle
D. Square
View answer and explanation
Correct Option: B
A triangle has three sides, whereas the others have four.
Q12Reasoning Ability
Medium
Find the next number: 2, 6, 12, 20, 30, ?
A. 38
B. 42
C. 40
D. 44
View answer and explanation
Correct Option: B
The terms are n(n + 1): 1×2, 2×3, 3×4, 4×5, 5×6, so the next is 6×7 = 42.
Q13Reasoning Ability
Easy
Find the next number: 3, 6, 12, 24, ?
A. 36
B. 48
C. 30
D. 42
View answer and explanation
Correct Option: B
Each term is twice the previous one.
Q14Reasoning Ability
Easy
Find the next number: 1, 4, 9, 16, 25, ?
A. 30
B. 36
C. 32
D. 35
View answer and explanation
Correct Option: B
These are the squares of the natural numbers; the next is 6² = 36.
Q15Reasoning Ability
Easy
Find the next letter: Z, X, V, T, ?
A. Q
B. R
C. S
D. P
View answer and explanation
Correct Option: B
Each letter is two places before the previous one.
Q16Reasoning Ability
Medium
Find the next number: 5, 11, 23, 47, ?
A. 94
B. 93
C. 95
D. 96
View answer and explanation
Correct Option: C
Each term is double the previous one plus 1: 47 × 2 + 1 = 95.
Q17Reasoning Ability
Easy
Find the next letter: B, E, H, K, ?
A. N
B. L
C. O
D. M
View answer and explanation
Correct Option: A
Each letter is three places after the previous one.
Q18Reasoning Ability
Easy
Find the next number: 100, 92, 84, 76, ?
A. 70
B. 68
C. 64
D. 66
View answer and explanation
Correct Option: B
The numbers decrease by 8 each time.
Q19Reasoning Ability
Easy
Find the next number: 2, 3, 5, 7, 11, 13, ?
A. 17
B. 19
C. 16
D. 15
View answer and explanation
Correct Option: A
These are the consecutive prime numbers; the next prime after 13 is 17.
Q20Reasoning Ability
Easy
If MANGO is written as NBOHP, how is APPLE written?
A. BQQLF
B. BQQMF
C. BPQMF
D. ZOOKD
View answer and explanation
Correct Option: B
Each letter is replaced by the next letter of the alphabet: A→B, P→Q, P→Q, L→M, E→F.
Q21Reasoning Ability
Easy
If A = 1, B = 2, ... Z = 26, the sum of the letter values of the word DOG is
A. 28
B. 27
C. 26
D. 24
View answer and explanation
Correct Option: C
D = 4, O = 15, G = 7, and 4 + 15 + 7 = 26.
Q22Reasoning Ability
Easy
If TABLE is written as 20 1 2 12 5, how is CHAIR written?
A. 3 8 1 9 18
B. 3 8 1 9 17
C. 3 7 1 9 18
D. 4 8 1 9 18
View answer and explanation
Correct Option: A
Each letter is replaced by its position in the alphabet: C = 3, H = 8, A = 1, I = 9, R = 18.
Q23Reasoning Ability
Easy
If CLOCK is written as DMPDL, how is TIME written?
A. UJNF
B. UKNF
C. SHLD
D. UJND
View answer and explanation
Correct Option: A
Each letter is shifted one place forward: T→U, I→J, M→N, E→F.
Q24Reasoning Ability
Hard
If FRIEND is written as HUMJTK, how is CANDLE written?
A. EDRIRM
B. EDIRRL
C. EDRIRL
D. DEIRRL
View answer and explanation
Correct Option: C
The shifts are +2, +3, +4, +5, +6, +7 for letters 1 to 6. So C→E, A→D, N→R, D→I, L→R, E→L.
Q25Reasoning Ability
Easy
If 2 is coded as 4, 3 as 9 and 4 as 16, then 6 is coded as
A. 18
B. 36
C. 24
D. 12
View answer and explanation
Correct Option: B
Each number is coded as its square.
Q26Reasoning Ability
Medium
Pointing to a photograph, a man says, "She is the daughter of my grandfather’s only son." How is the girl related to the man?
A. Aunt
B. Cousin
C. Mother
D. Sister
View answer and explanation
Correct Option: D
The man’s grandfather’s only son is the man’s father, and the father’s daughter is the man’s sister.
Q27Reasoning Ability
Medium
A is the brother of B. B is the sister of C. C is the father of D. How is A related to D?
A. Father
B. Grandfather
C. Uncle
D. Cousin
View answer and explanation
Correct Option: C
A and C are siblings. A is male, and C’s child is D, so A is D’s uncle.
Q28Reasoning Ability
Medium
P is the mother of Q. Q is the sister of R. R is the son of S. How is S related to P?
A. Father
B. Husband
C. Son
D. Brother
View answer and explanation
Correct Option: B
Q and R are siblings, so S is a parent of Q. P is Q’s mother, so S must be the father, who is P’s husband.
Q29Reasoning Ability
Easy
Rohan’s mother is the only daughter of Mohan. How is Mohan related to Rohan?
A. Paternal grandfather
B. Father
C. Uncle
D. Maternal grandfather
View answer and explanation
Correct Option: D
Mohan is the father of Rohan’s mother, so he is Rohan’s maternal grandfather.
Q30Reasoning Ability
Easy
A man walks 5 km north, then 3 km east and then 5 km south. How far is he from his starting point?
A. 8 km
B. 5 km
C. 13 km
D. 3 km
View answer and explanation
Correct Option: D
The north and south legs cancel, so he is 3 km east of the start.
Q31Reasoning Ability
Easy
Rahul faces north, turns 90° clockwise and then 180° anticlockwise. He now faces
A. West
B. East
C. South
D. North
View answer and explanation
Correct Option: A
90° clockwise from north is east. Turning 180° from east gives west.
Q32Reasoning Ability
Easy
A man walks 4 km east and then 3 km north. His shortest distance from the starting point is
A. 12 km
B. 1 km
C. 7 km
D. 5 km
View answer and explanation
Correct Option: D
By Pythagoras, √(4² + 3²) = 5 km.
Q33Reasoning Ability
Easy
Ram goes 6 m south, then turns west and goes 8 m, then turns north and goes 6 m. His position with respect to the starting point is
A. 8 m east
B. 8 m west
C. 14 m west
D. 6 m north
View answer and explanation
Correct Option: B
The south and north movements cancel, leaving 8 m to the west.
Q34Reasoning Ability
Easy
In a class of 40 students, Raj ranks 12th from the top. His rank from the bottom is
A. 27th
B. 29th
C. 30th
D. 28th
View answer and explanation
Correct Option: B
Rank from the bottom = 40 − 12 + 1 = 29.
Q35Reasoning Ability
Easy
In a row, A is 7th from the left and 12th from the right. The total number of persons in the row is
A. 17
B. 19
C. 18
D. 20
View answer and explanation
Correct Option: C
Total = 7 + 12 − 1 = 18.
Q36Reasoning Ability
Easy
A is taller than B, B is taller than C, D is taller than A, and E is shorter than C. Who is the tallest?
A. A
B. D
C. E
D. B
View answer and explanation
Correct Option: B
The order from tallest to shortest is D > A > B > C > E.
Q37Reasoning Ability
Medium
Statements: All flowers are trees. No tree is a stone. Conclusions: I. No flower is a stone. II. Some stones are flowers.
A. Neither I nor II follows
B. Both I and II follow
C. Only conclusion I follows
D. Only conclusion II follows
View answer and explanation
Correct Option: C
Flowers lie inside trees, and trees have no overlap with stones, so no flower is a stone. Conclusion II contradicts this.
Q38Reasoning Ability
Medium
Statements: Some pens are books. All books are tables. Conclusions: I. Some pens are tables. II. Some tables are pens.
A. Only conclusion II follows
B. Both I and II follow
C. Only conclusion I follows
D. Neither I nor II follows
View answer and explanation
Correct Option: B
The pens that are books are also tables, so some pens are tables, and the converse follows.
Q39Reasoning Ability
Medium
Statements: Some tables are chairs. Some chairs are beds. Conclusions: I. Some tables are beds. II. Some beds are tables.
A. Only conclusion II follows
B. Only conclusion I follows
C. Both I and II follow
D. Neither I nor II follows
View answer and explanation
Correct Option: D
Two “some” statements give no definite link between tables and beds, because the chairs may be different sets.
Q40Reasoning Ability
Medium
Statements: All pencils are pens. Some pens are erasers. Conclusions: I. Some pencils are erasers. II. Some erasers are pens.
A. Both I and II follow
B. Neither I nor II follows
C. Only conclusion II follows
D. Only conclusion I follows
View answer and explanation
Correct Option: C
The converse of “some pens are erasers” always holds, so II follows. The erasers need not overlap with pencils, so I does not follow.
Q41Reasoning Ability
Medium
If 5 March 2024 was a Tuesday, what day of the week was 25 March 2024?
A. Monday
B. Tuesday
C. Sunday
D. Wednesday
View answer and explanation
Correct Option: A
25 − 5 = 20 days later. 20 = 2 × 7 + 6, so the day moves 6 days ahead of Tuesday, to Monday.
Q42Reasoning Ability
Medium
The angle between the hour hand and the minute hand of a clock at 3:30 is
A. 60°
B. 90°
C. 75°
D. 105°
View answer and explanation
Correct Option: C
At 3:30 the hour hand is at 3.5 × 30 = 105° and the minute hand is at 180°. The angle is 75°.
Q43Reasoning Ability
Easy
Which of the following is a leap year?
A. 1900
B. 2100
C. 2024
D. 2022
View answer and explanation
Correct Option: C
A year divisible by 4 is a leap year, except century years, which must be divisible by 400. So 2024 is a leap year, whereas 2100 and 1900 are not.
Q44Reasoning Ability
Easy
If “+” means “−” and “−” means “+”, then 15 + 5 − 3 = ?
A. 23
B. 7
C. 17
D. 13
View answer and explanation
Correct Option: D
After substituting the signs, the expression is 15 − 5 + 3 = 13.
Q45Reasoning Ability
Easy
Find the missing number: 2 → 6, 3 → 12, 4 → 20, 5 → ?
A. 28
B. 25
C. 36
D. 30
View answer and explanation
Correct Option: D
The rule is n × (n + 1): 2×3, 3×4, 4×5, so 5×6 = 30.
Q46Reasoning Ability
Medium
If 3 ⊕ 4 = 25 and 5 ⊕ 12 = 169, then 8 ⊕ 15 = ?
A. 233
B. 161
C. 23
D. 289
View answer and explanation
Correct Option: D
The rule is a² + b²: 3² + 4² = 25 and 5² + 12² = 169. So 8² + 15² = 64 + 225 = 289.
Q47Reasoning Ability
Easy
Arrange in a meaningful order: 1. Seed 2. Plant 3. Fruit 4. Flower 5. Tree
A. 2 1 5 4 3
B. 1 5 2 4 3
C. 1 2 5 4 3
D. 1 2 4 5 3
View answer and explanation
Correct Option: C
The natural sequence is seed → plant → tree → flower → fruit.
Q48Reasoning Ability
Medium
Statement: If it rains, the match will be cancelled. The match was not cancelled. Which conclusion is definitely true?
A. It rained
B. It may have rained
C. The match was played in the rain
D. It did not rain
View answer and explanation
Correct Option: D
If the match was not cancelled, the condition “it rains” cannot have been true (contrapositive).
Q49Reasoning Ability
Easy
Statement: Only students with ID cards are allowed in the library. Ravi is allowed in the library. Which conclusion is definitely true?
A. Ravi has an ID card
B. Ravi has no ID card
C. All students are allowed in the library
D. Ravi is not a student
View answer and explanation
Correct Option: A
Since permission requires an ID card, anyone who is allowed in must have one.
Q50Reasoning Ability
Medium
Statement: All the mangoes in the basket are ripe. Some fruits in the basket are not ripe. Which must be true?
A. Some mangoes in the basket are not ripe
B. All fruits in the basket are mangoes
C. No fruit in the basket is ripe
D. Some fruits in the basket are not mangoes
View answer and explanation
Correct Option: D
The fruits that are not ripe cannot be mangoes, since all mangoes there are ripe.
Q51General Awareness
Easy
Who won the First Battle of Panipat in 1526?
A. Humayun
B. Sher Shah Suri
C. Akbar
D. Babur
View answer and explanation
Correct Option: D
Babur defeated Ibrahim Lodi, the last Sultan of Delhi, and founded the Mughal Empire.
Q52General Awareness
Medium
Dholavira, a major site of the Indus Valley Civilisation, is located in
A. Gujarat
B. Punjab
C. Rajasthan
D. Haryana
View answer and explanation
Correct Option: A
Dholavira is in the Kutch district of Gujarat and is known for its water conservation system.
Q53General Awareness
Easy
After the Kalinga war, Emperor Ashoka adopted
A. Hinduism
B. Buddhism
C. Jainism
D. Sikhism
View answer and explanation
Correct Option: B
The destruction of the war moved him to follow Buddhism and the policy of dhamma.
Q54General Awareness
Easy
The Quit India Movement was launched in
A. 1920
B. 1930
C. 1942
D. 1919
View answer and explanation
Correct Option: C
It was started by Mahatma Gandhi at the Bombay session of the Congress in August 1942, with the call “Do or Die”.
Q55General Awareness
Easy
The Jallianwala Bagh massacre took place in
A. Lahore
B. Amritsar
C. Ludhiana
D. Delhi
View answer and explanation
Correct Option: B
On 13 April 1919 troops under General Dyer fired on a gathering at Jallianwala Bagh in Amritsar.
Q56General Awareness
Medium
Who was the first Indian Governor-General of independent India?
A. C. Rajagopalachari
B. Rajendra Prasad
C. Lord Mountbatten
D. Jawaharlal Nehru
View answer and explanation
Correct Option: A
Mountbatten was the last Viceroy and the first Governor-General. C. Rajagopalachari succeeded him in 1948.
Q57General Awareness
Medium
The practice of sati was abolished in 1829 by
A. Lord Curzon
B. Lord William Bentinck
C. Lord Dalhousie
D. Lord Cornwallis
View answer and explanation
Correct Option: B
The regulation was passed with the support of Raja Ram Mohan Roy.
Q58General Awareness
Medium
The Doctrine of Lapse was introduced by
A. Lord Dalhousie
B. Lord Canning
C. Lord Ripon
D. Lord Wellesley
View answer and explanation
Correct Option: A
Under this policy, a princely state without a natural male heir could be annexed by the British.
Q59General Awareness
Easy
The longest river within India is
A. Ganga
B. Brahmaputra
C. Godavari
D. Yamuna
View answer and explanation
Correct Option: A
The Ganga is about 2,525 km long. The Brahmaputra is longer overall, but it spends part of its course in China and Bangladesh.
Q60General Awareness
Medium
The Tropic of Cancer passes through how many Indian states?
A. 8
B. 10
C. 6
D. 4
View answer and explanation
Correct Option: A
It passes through Gujarat, Rajasthan, Madhya Pradesh, Chhattisgarh, Jharkhand, West Bengal, Tripura and Mizoram.
Q61General Awareness
Easy
The largest Indian state by area is
A. Maharashtra
B. Uttar Pradesh
C. Madhya Pradesh
D. Rajasthan
View answer and explanation
Correct Option: D
Rajasthan covers about 3.42 lakh sq km.
Q62General Awareness
Easy
Chilika Lake, the largest coastal lagoon in India, is in
A. Tamil Nadu
B. West Bengal
C. Andhra Pradesh
D. Odisha
View answer and explanation
Correct Option: D
Chilika lies on the east coast in Odisha and is a Ramsar site.
Q63General Awareness
Easy
The Deccan Plateau is bounded on the west by
A. the Aravalli Range
B. the Western Ghats
C. the Vindhya Range
D. the Eastern Ghats
View answer and explanation
Correct Option: B
The Western Ghats form the western edge, and the Eastern Ghats the eastern edge of the plateau.
Q64General Awareness
Easy
Which soil is considered best for growing cotton?
A. Alluvial soil
B. Desert soil
C. Laterite soil
D. Black soil (regur)
View answer and explanation
Correct Option: D
Black soil retains moisture well, so it supports cotton in the Deccan region.
Q65General Awareness
Easy
The Prime Meridian, the line of 0° longitude, passes through
A. Greenwich, London
B. Washington D.C.
C. New Delhi
D. Paris
View answer and explanation
Correct Option: A
It divides the Earth into the Eastern and Western Hemispheres.
Q66General Awareness
Easy
The Constitution of India came into force on
A. 15 August 1947
B. 26 November 1949
C. 2 October 1950
D. 26 January 1950
View answer and explanation
Correct Option: D
It was adopted on 26 November 1949 and came into force on 26 January 1950, which is celebrated as Republic Day.
Q67General Awareness
Medium
The Fundamental Duties were added to the Constitution by the
A. 44th Amendment
B. 42nd Amendment
C. 73rd Amendment
D. 1st Amendment
View answer and explanation
Correct Option: B
The 42nd Amendment (1976), on the Swaran Singh Committee’s recommendation, added Part IVA (Article 51A).
Q68General Awareness
Easy
The right to life and personal liberty is guaranteed under
A. Article 19
B. Article 21
C. Article 32
D. Article 14
View answer and explanation
Correct Option: B
Article 21 says that no person shall be deprived of life or personal liberty except by procedure established by law.
Q69General Awareness
Easy
The minimum age to be elected as President of India is
A. 40 years
B. 25 years
C. 35 years
D. 30 years
View answer and explanation
Correct Option: C
A candidate must be a citizen of India who has completed 35 years and is qualified for election to the Lok Sabha.
Q70General Awareness
Medium
The maximum strength of the Rajya Sabha is
A. 552
B. 250
C. 245
D. 238
View answer and explanation
Correct Option: B
It has up to 238 elected members and 12 nominated members.
Q71General Awareness
Easy
A Money Bill can be introduced only in
A. a joint sitting of both Houses
B. either House
C. the Rajya Sabha
D. the Lok Sabha
View answer and explanation
Correct Option: D
The Rajya Sabha can only make recommendations on it, within 14 days.
Q72General Awareness
Easy
The 73rd Constitutional Amendment Act is related to
A. the Goods and Services Tax
B. Municipalities
C. Fundamental Duties
D. Panchayati Raj
View answer and explanation
Correct Option: D
It gave constitutional status to Panchayati Raj institutions in 1992 (in force from 1993).
Q73General Awareness
Easy
The Chairman of the Drafting Committee of the Constituent Assembly was
A. Jawaharlal Nehru
B. Rajendra Prasad
C. Sardar Vallabhbhai Patel
D. B. R. Ambedkar
View answer and explanation
Correct Option: D
Dr. B. R. Ambedkar chaired the committee, and Dr. Rajendra Prasad was the President of the Assembly.
Q74General Awareness
Easy
The Reserve Bank of India was established in
A. 1949
B. 1969
C. 1935
D. 1947
View answer and explanation
Correct Option: C
The RBI began working on 1 April 1935 and was nationalised in 1949.
Q75General Awareness
Easy
The Goods and Services Tax (GST) came into effect in India on
A. 1 January 2018
B. 1 April 2017
C. 1 April 2016
D. 1 July 2017
View answer and explanation
Correct Option: D
It replaced many indirect taxes of the Centre and states with a single tax on goods and services.
Q76General Awareness
Easy
The repo rate is the rate at which
A. the RBI borrows from commercial banks
B. commercial banks lend to the public
C. the RBI lends short-term funds to commercial banks
D. banks lend to one another
View answer and explanation
Correct Option: C
The reverse repo is the rate at which the RBI borrows from banks.
Q77General Awareness
Easy
The Planning Commission was replaced by NITI Aayog in
A. 2015
B. 2010
C. 2017
D. 2012
View answer and explanation
Correct Option: A
NITI Aayog was set up on 1 January 2015 as a policy think tank of the Government of India.
Q78General Awareness
Easy
The headquarters of the Reserve Bank of India is located in
A. New Delhi
B. Kolkata
C. Chennai
D. Mumbai
View answer and explanation
Correct Option: D
Though it was first set up in Kolkata, the RBI was moved to Mumbai in 1937.
Q79General Awareness
Medium
The fiscal deficit of a government is
A. its total expenditure minus its total receipts excluding borrowings
B. its revenue expenditure minus its revenue receipts
C. its total receipts minus its total expenditure
D. its capital expenditure alone
View answer and explanation
Correct Option: A
It shows how much the government must borrow in a year to meet its spending.
Q80General Awareness
Easy
The SI unit of force is
A. joule
B. watt
C. pascal
D. newton
View answer and explanation
Correct Option: D
One newton is the force that gives a mass of 1 kg an acceleration of 1 m/s².
Q81General Awareness
Easy
The speed of light in vacuum is approximately
A. 3 × 10⁵ m/s
B. 3 × 10⁶ m/s
C. 3 × 10⁸ m/s
D. 3 × 10¹⁰ m/s
View answer and explanation
Correct Option: C
It is 299 792 458 m/s, about 3 × 10⁸ m/s.
Q82General Awareness
Easy
A dentist uses which type of mirror to see an enlarged image of a tooth?
A. Convex
B. Plane
C. Concave
D. Cylindrical
View answer and explanation
Correct Option: C
A concave mirror forms an enlarged, erect image when the object is placed within its focal length.
Q83General Awareness
Easy
The SI unit of frequency is
A. hertz
B. decibel
C. candela
D. tesla
View answer and explanation
Correct Option: A
One hertz is one cycle per second.
Q84General Awareness
Easy
The chemical formula of common salt is
A. KCl
B. CaCl₂
C. NaCl
D. Na₂CO₃
View answer and explanation
Correct Option: C
Common salt is sodium chloride.
Q85General Awareness
Easy
The pH of pure water at 25 °C is
A. 14
B. 5
C. 7
D. 0
View answer and explanation
Correct Option: C
A pH of 7 is neutral, below 7 is acidic and above 7 is basic.
Q86General Awareness
Easy
Which gas is mostly used in fire extinguishers?
A. Carbon dioxide
B. Oxygen
C. Hydrogen
D. Nitrogen dioxide
View answer and explanation
Correct Option: A
Carbon dioxide is heavier than air and does not support combustion, so it smothers the fire.
Q87General Awareness
Easy
The rusting of iron is an example of
A. neutralisation
B. oxidation
C. sublimation
D. reduction
View answer and explanation
Correct Option: B
Iron reacts with oxygen and moisture to form hydrated iron(III) oxide.
Q88General Awareness
Easy
The powerhouse of the cell is the
A. ribosome
B. nucleus
C. Golgi apparatus
D. mitochondrion
View answer and explanation
Correct Option: D
Mitochondria produce most of the ATP, the energy currency of the cell.
Q89General Awareness
Easy
A deficiency of vitamin C causes
A. rickets
B. scurvy
C. night blindness
D. beriberi
View answer and explanation
Correct Option: B
Vitamin C is needed for making collagen. Rickets is due to vitamin D, beriberi to B1 and night blindness to vitamin A.
Q90General Awareness
Medium
Which blood group is called the universal donor?
A. AB positive
B. O negative
C. A positive
D. B negative
View answer and explanation
Correct Option: B
O negative red cells have no A, B or Rh antigens, so they can be given to almost any recipient.
Q91General Awareness
Easy
Photosynthesis takes place in the
A. chloroplasts
B. lysosomes
C. vacuoles
D. mitochondria
View answer and explanation
Correct Option: A
The chlorophyll in the chloroplasts captures light energy to make glucose from carbon dioxide and water.
Q92General Awareness
Easy
The red pigment in human blood that carries oxygen contains
A. iron
B. calcium
C. copper
D. magnesium
View answer and explanation
Correct Option: A
Haemoglobin has an iron-containing haem group. Chlorophyll contains magnesium.
Q93General Awareness
Easy
The first Indian to win a Nobel Prize was
A. Rabindranath Tagore
B. Amartya Sen
C. C. V. Raman
D. Mother Teresa
View answer and explanation
Correct Option: A
Tagore won the Nobel Prize in Literature in 1913 for Gitanjali.
Q94General Awareness
Easy
The Bharat Ratna is
A. the highest gallantry award of India
B. the highest civilian award of India
C. an award for literature only
D. an award for sports only
View answer and explanation
Correct Option: B
It is given for exceptional service in any field of human endeavour.
Q95General Awareness
Easy
The national animal of India is the
A. elephant
B. tiger
C. lion
D. leopard
View answer and explanation
Correct Option: B
The Bengal tiger was adopted as the national animal in 1973 under Project Tiger.
Q96General Awareness
Easy
Major Dhyan Chand is associated with the sport of
A. football
B. hockey
C. cricket
D. wrestling
View answer and explanation
Correct Option: B
He won Olympic gold medals with India in 1928, 1932 and 1936, and his birthday, 29 August, is National Sports Day.
Q97General Awareness
Easy
The book “The Discovery of India” was written by
A. Mahatma Gandhi
B. Sardar Patel
C. Jawaharlal Nehru
D. Rabindranath Tagore
View answer and explanation
Correct Option: C
Nehru wrote it in Ahmednagar Fort jail in 1944.
Q98General Awareness
Easy
In computing, CPU stands for
A. Control Processing Utility
B. Computer Personal Unit
C. Central Program Unit
D. Central Processing Unit
View answer and explanation
Correct Option: D
The CPU executes the instructions of a program and is often called the brain of the computer.
Q99General Awareness
Easy
The ozone layer protects life on Earth from
A. sound waves
B. infrared rays
C. cosmic dust
D. harmful ultraviolet rays of the Sun
View answer and explanation
Correct Option: D
Ozone in the stratosphere absorbs most of the Sun’s UV-B and UV-C radiation.
Q100General Awareness
Easy
World Environment Day is celebrated every year on
A. 22 April
B. 21 March
C. 5 June
D. 16 September
View answer and explanation
Correct Option: C
It has been celebrated since 1974 on 5 June. Earth Day is on 22 April.
Q101Mechanical Engineering (SSC JE)
Easy
The zeroth law of thermodynamics is the basis for the measurement of
A. pressure
B. work
C. entropy
D. temperature
View answer and explanation
Correct Option: D
If two bodies are each in thermal equilibrium with a third, they are in equilibrium with each other. This makes a thermometer meaningful.
Q102Mechanical Engineering (SSC JE)
Easy
A Carnot engine works between reservoirs at 800 K and 300 K. Its efficiency is
A. 60 percent
B. 72.5 percent
C. 37.5 percent
D. 62.5 percent
View answer and explanation
Correct Option: D
η = 1 − T2/T1 = 1 − 300/800 = 0.625.
Q103Mechanical Engineering (SSC JE)
Easy
The value of the universal gas constant is
A. 83.14 kJ/kmol·K
B. 0.287 kJ/kmol·K
C. 8.314 kJ/kmol·K
D. 1.4 kJ/kmol·K
View answer and explanation
Correct Option: C
R̄ = 8.314 kJ/kmol·K. The gas constant of air, 0.287 kJ/kg·K, is R̄ divided by the molar mass 28.97.
Q104Mechanical Engineering (SSC JE)
Easy
For a closed system undergoing a complete cycle, the net heat transfer is equal to
A. the change in internal energy
B. the change in enthalpy
C. zero
D. the net work done
View answer and explanation
Correct Option: D
Over a cycle ΔU = 0, so by the first law ∮δQ = ∮δW.
Q105Mechanical Engineering (SSC JE)
Easy
The ratio of specific heats γ for air at ordinary temperatures is about
A. 1.33
B. 1.67
C. 1.0
D. 1.4
View answer and explanation
Correct Option: D
Air is mostly diatomic, with γ = Cp/Cv ≈ 1.4. Monatomic gases give 1.67.
Q106Mechanical Engineering (SSC JE)
Easy
In a reversible adiabatic process, the entropy of the system
A. decreases
B. increases
C. remains constant
D. becomes zero
View answer and explanation
Correct Option: C
With δQ = 0 and no irreversibility, dS = δQrev/T = 0. Such a process is called isentropic.
Q107Mechanical Engineering (SSC JE)
Easy
For an ideal gas, Cp − Cv is equal to
A. the characteristic gas constant R
B. γ
C. zero
D. the universal gas constant for every gas
View answer and explanation
Correct Option: A
This is Mayer’s relation, Cp − Cv = R, where R is the specific gas constant of that gas.
Q108Mechanical Engineering (SSC JE)
Easy
A throttling process is
A. isothermal for every fluid
B. isenthalpic
C. isochoric
D. isentropic
View answer and explanation
Correct Option: B
In throttling through a valve or porous plug, h1 = h2 (adiabatic, no work, negligible change in kinetic energy), but entropy increases.
Q109Mechanical Engineering (SSC JE)
Hard
The air standard efficiency of an Otto cycle with compression ratio 8 and γ = 1.4 is about
A. 43.5 percent
B. 56.5 percent
C. 75 percent
D. 63.5 percent
View answer and explanation
Correct Option: B
η = 1 − 1/r^(γ−1) = 1 − 1/8^0.4 = 1 − 1/2.297 = 0.565.
Q110Mechanical Engineering (SSC JE)
Medium
The critical temperature of water is about
A. 374 °C
B. 273 °C
C. 100 °C
D. 547 °C
View answer and explanation
Correct Option: A
At 374 °C and 221 bar the liquid and vapour phases become indistinguishable.
Q111Mechanical Engineering (SSC JE)
Easy
The Kelvin-Planck statement of the second law deals with
A. a heat engine
B. a heat pump
C. an adiabatic compressor
D. a refrigerator
View answer and explanation
Correct Option: A
No cyclic heat engine can convert all the heat from a single reservoir into work. The Clausius statement deals with refrigerators.
Q112Mechanical Engineering (SSC JE)
Medium
Reheating the steam in a Rankine cycle mainly
A. improves the dryness of the steam at the turbine exhaust
B. lowers the boiler pressure
C. reduces the work output of the turbine
D. increases the condenser pressure
View answer and explanation
Correct Option: A
Passing the partly expanded steam through the boiler again reduces moisture in the last stages, which protects the blades.
Q113Mechanical Engineering (SSC JE)
Easy
The SI unit of kinematic viscosity is
A. N/m²
B. kg/m·s
C. N·s/m²
D. m²/s
View answer and explanation
Correct Option: D
ν = μ/ρ, so its unit is m²/s. N·s/m² is the unit of dynamic viscosity.
Q114Mechanical Engineering (SSC JE)
Hard
A difference of 100 mm of mercury (density 13 600 kg/m³) corresponds to a pressure difference of about
A. 13.3 kPa
B. 133 kPa
C. 0.98 kPa
D. 9.81 kPa
View answer and explanation
Correct Option: A
Δp = ρgh = 13 600 × 9.81 × 0.1 = 13 342 Pa ≈ 13.3 kPa.
Q115Mechanical Engineering (SSC JE)
Easy
A Pitot tube is used to measure
A. the density of a fluid
B. the viscosity of a fluid
C. the surface tension
D. the local velocity of flow
View answer and explanation
Correct Option: D
It senses the stagnation pressure, and with the static pressure gives the velocity head.
Q116Mechanical Engineering (SSC JE)
Easy
The Reynolds number is the ratio of
A. viscous forces to inertial forces
B. inertial forces to viscous forces
C. pressure forces to surface tension forces
D. gravity forces to inertial forces
View answer and explanation
Correct Option: B
Re = ρVD/μ. It decides whether flow is laminar or turbulent.
Q117Mechanical Engineering (SSC JE)
Easy
Cavitation in a pump occurs when the pressure at some point in the liquid falls below
A. the atmospheric pressure
B. the delivery pressure
C. the vapour pressure of the liquid at that temperature
D. the critical pressure
View answer and explanation
Correct Option: C
Vapour bubbles form and later collapse violently on reaching higher pressure, causing noise, vibration and pitting.
Q118Mechanical Engineering (SSC JE)
Medium
A Kaplan turbine is
A. an impulse turbine for high heads
B. a radial flow turbine for very high heads
C. a tangential flow turbine
D. an axial flow reaction turbine for low heads
View answer and explanation
Correct Option: D
The Kaplan runner has adjustable blades and suits large discharges at low heads.
Q119Mechanical Engineering (SSC JE)
Medium
The overall efficiency of a centrifugal pump is the product of
A. mechanical and thermal efficiencies
B. volumetric and thermal efficiencies
C. hydraulic and thermal efficiencies
D. hydraulic, mechanical and volumetric efficiencies
View answer and explanation
Correct Option: D
η = ηh × ηm × ηv, covering the losses in the flow passages, the bearings and the leakage.
Q120Mechanical Engineering (SSC JE)
Easy
An air vessel is fitted to a reciprocating pump to
A. cool the cylinder
B. prime the pump
C. obtain a uniform discharge and reduce friction and acceleration head
D. increase the suction lift
View answer and explanation
Correct Option: C
The vessel absorbs surges of flow, so a steadier stream flows in the pipe and the pump can run at higher speed.
Q121Mechanical Engineering (SSC JE)
Easy
In a hydraulic press, the small piston has an area of 10 cm² and the large piston 500 cm². A force of 200 N on the small piston produces a force on the large piston of
A. 100 kN
B. 10 kN
C. 1 kN
D. 4 kN
View answer and explanation
Correct Option: B
Pressure is the same on both pistons: F2 = F1 × (A2/A1) = 200 × 50 = 10 000 N.
Q122Mechanical Engineering (SSC JE)
Easy
In the Buckingham π theorem, if there are n variables and m fundamental dimensions, the number of dimensionless groups is
A. n + m
B. n − m
C. n × m
D. m − n
View answer and explanation
Correct Option: B
The variables are reduced to (n − m) independent dimensionless π terms.
Q123Mechanical Engineering (SSC JE)
Medium
Separation of the boundary layer from a surface takes place because of
A. a high free stream velocity only
B. zero velocity at the free stream
C. a favourable pressure gradient
D. an adverse pressure gradient
View answer and explanation
Correct Option: D
When the pressure rises in the flow direction, the fluid near the wall loses momentum and the flow reverses.
Q124Mechanical Engineering (SSC JE)
Medium
The draft tube of a reaction turbine
A. converts kinetic energy of the exit water into pressure and lets the runner be set above the tail water
B. works as a governor
C. increases the speed of the runner
D. reduces the discharge
View answer and explanation
Correct Option: A
A gradually widening tube recovers energy and keeps the runner exit pressure below atmospheric, adding to the effective head.
Q125Mechanical Engineering (SSC JE)
Easy
Air of density 1.2 kg/m³ flows at 10 m/s through a duct of area 0.01 m². The mass flow rate is
A. 0.12 kg/s
B. 0.012 kg/s
C. 12 kg/s
D. 1.2 kg/s
View answer and explanation
Correct Option: A
ṁ = ρAV = 1.2 × 0.01 × 10 = 0.12 kg/s.
Q126Mechanical Engineering (SSC JE)
Easy
The flow of a gas is supersonic when the Mach number is
A. less than 1
B. greater than 1
C. equal to 0
D. equal to 0.5
View answer and explanation
Correct Option: B
Mach number M = V/c, where c is the speed of sound. M = 1 is sonic flow.
Q127Mechanical Engineering (SSC JE)
Easy
Fourier’s law of heat conduction states that the heat flux is proportional to
A. the square of the temperature
B. the temperature gradient
C. the surface area only
D. the fourth power of temperature
View answer and explanation
Correct Option: B
q = −k dT/dx, with the negative sign showing that heat flows from hot to cold.
Q128Mechanical Engineering (SSC JE)
Easy
A plane wall has a thermal conductivity of 0.5 W/m·K and a thickness of 0.2 m. The temperature difference across it is 40 °C. The heat flux is
A. 4 W/m²
B. 100 W/m²
C. 10 W/m²
D. 1000 W/m²
View answer and explanation
Correct Option: B
q = k ΔT / L = 0.5 × 40 / 0.2 = 100 W/m².
Q129Mechanical Engineering (SSC JE)
Easy
According to the Stefan-Boltzmann law, if the absolute temperature of a black body is doubled, the emissive power increases by a factor of
A. 8
B. 4
C. 2
D. 16
View answer and explanation
Correct Option: D
E = σT⁴, so doubling T gives 2⁴ = 16 times the emissive power.
Q130Mechanical Engineering (SSC JE)
Medium
The Nusselt number is defined as
A. hL / k
B. ρVL / μ
C. V / c
D. μ cp / k
View answer and explanation
Correct Option: A
It is the ratio of convective to conductive heat transfer across a boundary.
Q131Mechanical Engineering (SSC JE)
Easy
Fins are provided on a surface to
A. lower the thermal conductivity
B. increase the weight
C. increase the surface area for heat transfer
D. reduce the heat transfer
View answer and explanation
Correct Option: C
More surface area to the fluid helps when the heat transfer coefficient is low, as with air.
Q132Mechanical Engineering (SSC JE)
Medium
The critical radius of insulation for a cylinder is given by
A. kh
B. h / k
C. 2k / h
D. k / h
View answer and explanation
Correct Option: D
Insulation below this radius increases the heat loss, because the outer area grows faster than the resistance of the insulation.
Q133Mechanical Engineering (SSC JE)
Easy
Hooke’s law is valid up to the
A. ultimate stress
B. yield point of every material
C. proportional limit
D. breaking point
View answer and explanation
Correct Option: C
Stress is proportional to strain only up to the proportional limit.
Q134Mechanical Engineering (SSC JE)
Easy
The modulus of elasticity of mild steel is about
A. 100 GPa
B. 200 GPa
C. 70 GPa
D. 400 GPa
View answer and explanation
Correct Option: B
Steel is about 200 GPa, aluminium about 70 GPa and cast iron around 100 GPa.
Q135Mechanical Engineering (SSC JE)
Hard
A 20 mm diameter rod carries an axial pull of 100 kN. The stress developed is about
A. 159 MPa
B. 637 MPa
C. 31.8 MPa
D. 318 MPa
View answer and explanation
Correct Option: D
A = π × 20²/4 = 314.2 mm². σ = 100 000 / 314.2 = 318.3 MPa.
Q136Mechanical Engineering (SSC JE)
Medium
For brittle materials, the most suitable theory of failure is
A. the maximum shear strain energy theory
B. the distortion energy theory (von Mises)
C. the maximum shear stress theory (Tresca)
D. the maximum principal stress theory (Rankine)
View answer and explanation
Correct Option: D
Brittle materials fail by fracture when the largest principal stress reaches the ultimate strength, as the Rankine theory assumes.
Q137Mechanical Engineering (SSC JE)
Easy
In the Brinell hardness test, the indenter is
A. a diamond pyramid
B. a hardened steel (or tungsten carbide) ball
C. a steel cone
D. a diamond cone
View answer and explanation
Correct Option: B
Brinell uses a ball. Vickers uses a diamond pyramid and Rockwell C uses a diamond cone.
Q138Mechanical Engineering (SSC JE)
Easy
A simply supported beam of span 4 m carries a central point load of 10 kN. The maximum bending moment is
A. 40 kN·m
B. 10 kN·m
C. 20 kN·m
D. 5 kN·m
View answer and explanation
Correct Option: B
M = WL/4 = 10 × 4 / 4 = 10 kN·m.
Q139Mechanical Engineering (SSC JE)
Easy
A point of contraflexure on a beam is a point where
A. the deflection is maximum
B. the slope is zero
C. the shear force is maximum
D. the bending moment changes sign
View answer and explanation
Correct Option: D
At such a point the beam changes from sagging to hogging, and the moment is usually zero.
Q140Mechanical Engineering (SSC JE)
Easy
In a thin cylindrical shell under internal pressure, the ratio of hoop stress to longitudinal stress is
A. 4
B. 0.5
C. 2
D. 1
View answer and explanation
Correct Option: C
σh = pd/2t and σl = pd/4t, so the ratio is 2.
Q141Mechanical Engineering (SSC JE)
Easy
Charpy and Izod impact tests measure
A. the toughness of a material
B. the fatigue limit of a material
C. the creep strength of a material
D. the hardness of a material
View answer and explanation
Correct Option: A
The energy absorbed by a notched specimen when it breaks is a measure of toughness.
Q142Mechanical Engineering (SSC JE)
Easy
The factor of safety based on the ultimate strength is the ratio of
A. working stress to ultimate stress
B. ultimate stress to working (allowable) stress
C. ultimate load to yield load
D. yield stress to ultimate stress
View answer and explanation
Correct Option: B
FOS = σu/σw. Ductile materials are often based on yield stress instead.
Q143Mechanical Engineering (SSC JE)
Easy
The number of degrees of freedom of a planar four-bar mechanism is
A. 3
B. 1
C. 2
D. 0
View answer and explanation
Correct Option: B
Using Gruebler’s equation F = 3(n − 1) − 2j − h = 3 × 3 − 2 × 4 − 0 = 1.
Q144Mechanical Engineering (SSC JE)
Easy
A flywheel is used to
A. balance the reciprocating masses
B. reduce the fluctuation of speed during a cycle by storing energy
C. transmit power between shafts
D. control the mean speed against changes in load
View answer and explanation
Correct Option: B
It absorbs energy when the speed rises and gives it back when the speed falls. A governor controls the mean speed.
Q145Mechanical Engineering (SSC JE)
Easy
A governor in an engine is used to
A. increase the torque
B. reduce vibrations
C. maintain the mean speed when the load varies
D. reduce the fluctuations in speed within a cycle
View answer and explanation
Correct Option: C
It adjusts the fuel supply to the engine in response to load changes.
Q146Mechanical Engineering (SSC JE)
Easy
A gear has a pitch circle diameter of 120 mm and 40 teeth. Its module is
A. 30 mm
B. 4.8 mm
C. 3 mm
D. 0.33 mm
View answer and explanation
Correct Option: C
m = d/z = 120/40 = 3 mm.
Q147Mechanical Engineering (SSC JE)
Easy
The pressure angle commonly used for standard involute gear teeth is
A. 45°
B. 60°
C. 5°
D. 20°
View answer and explanation
Correct Option: D
14.5° was used earlier but 20° full-depth teeth are now standard because they are stronger and avoid interference with fewer teeth.
Q148Mechanical Engineering (SSC JE)
Easy
For a flat belt drive, the ratio of tight side to slack side tension is
A. e^(−μθ)
B. μθ
C. e^(μθ)
D. θ/μ
View answer and explanation
Correct Option: C
T1/T2 = e^(μθ), where θ is the angle of contact in radians.
Q149Mechanical Engineering (SSC JE)
Medium
For a rotating system to be in static balance, it is necessary that
A. the resultant couple is zero only
B. the speed is zero
C. the resultant centrifugal force is zero
D. the shaft is rigid
View answer and explanation
Correct Option: C
Static balance needs ΣF = 0. Dynamic balance also needs the resultant couple to be zero.
Q150Mechanical Engineering (SSC JE)
Hard
A spring-mass system has a stiffness of 3600 N/m and a mass of 4 kg. Its natural frequency is
A. 60 rad/s
B. 30 rad/s
C. 900 rad/s
D. 15 rad/s
View answer and explanation
Correct Option: B
ωn = √(k/m) = √(3600/4) = √900 = 30 rad/s.
Q151Mechanical Engineering (SSC JE)
Medium
The base circle of a cam is
A. the smallest circle drawn from the cam centre tangent to the cam profile
B. the circle that passes through the pitch point
C. the circle through the follower tip
D. the largest circle that can be drawn on the cam
View answer and explanation
Correct Option: A
The follower is at its lowest position when it touches the base circle.
Q152Mechanical Engineering (SSC JE)
Easy
A Hooke’s joint is used to connect two shafts which
A. are collinear
B. are parallel
C. are perpendicular and do not intersect
D. intersect at an angle
View answer and explanation
Correct Option: D
A universal joint transmits motion between intersecting shafts, though the speed of the driven shaft fluctuates.
Q153Mechanical Engineering (SSC JE)
Easy
The Goodman diagram is used in the design of machine members subjected to
A. fatigue (fluctuating loads)
B. impact loads only
C. static loads only
D. thermal loads only
View answer and explanation
Correct Option: A
It relates the mean stress and the alternating stress for a given factor of safety against fatigue failure.
Q154Mechanical Engineering (SSC JE)
Medium
For most steels, the endurance limit is roughly
A. 0.2 times the ultimate tensile strength
B. 1.2 times the ultimate tensile strength
C. 0.9 times the ultimate tensile strength
D. half of the ultimate tensile strength
View answer and explanation
Correct Option: D
For steels with Sut below about 1400 MPa, Se′ ≈ 0.5 Sut for a polished specimen.
Q155Mechanical Engineering (SSC JE)
Medium
The taper on a standard sunk key is generally
A. zero
B. 1 in 100
C. 1 in 20
D. 1 in 10
View answer and explanation
Correct Option: B
Taper keys are tapered on the top at 1 in 100 so that driving them in makes a tight fit.
Q156Mechanical Engineering (SSC JE)
Hard
A deep groove ball bearing has a dynamic load rating C of 20 kN and carries an equivalent load of 10 kN. Its rated life L10 is
A. 2 million revolutions
B. 8 million revolutions
C. 4 million revolutions
D. 16 million revolutions
View answer and explanation
Correct Option: B
For ball bearings L10 = (C/P)³ = 2³ = 8 million revolutions.
Q157Mechanical Engineering (SSC JE)
Medium
The Wahl factor in a helical spring accounts for
A. the effect of direct shear and the curvature of the coil
B. the length of the spring
C. the surface finish
D. the number of active coils
View answer and explanation
Correct Option: A
The factor K = (4C − 1)/(4C − 4) + 0.615/C corrects the simple torsion formula for these effects.
Q158Mechanical Engineering (SSC JE)
Easy
Stress concentration at a change of section can be reduced by
A. increasing the surface roughness
B. providing a generous fillet radius
C. making the corner sharp
D. adding a small hole near the corner
View answer and explanation
Correct Option: B
A smooth transition lets the force flow lines change direction gradually.
Q159Mechanical Engineering (SSC JE)
Medium
A hollow shaft compared with a solid shaft of the same weight and material is
A. equal in strength
B. weaker in torsion
C. cheaper to make
D. stronger and stiffer in torsion
View answer and explanation
Correct Option: D
Material removed from the centre carries little stress. Placing it farther out raises the polar moment of inertia.
Q160Mechanical Engineering (SSC JE)
Easy
A key may fail by
A. corrosion only
B. shearing and crushing
C. buckling only
D. creep only
View answer and explanation
Correct Option: B
The torque is transmitted by shear across the key and by bearing (crushing) on its sides.
Q161Mechanical Engineering (SSC JE)
Easy
In a four-stroke engine, one power stroke occurs in every
A. four revolutions of the crankshaft
B. two revolutions of the crankshaft
C. half a revolution of the crankshaft
D. one revolution of the crankshaft
View answer and explanation
Correct Option: B
Four strokes take 720° of crank rotation, giving one power stroke every two revolutions.
Q162Mechanical Engineering (SSC JE)
Easy
The cetane number is a measure of
A. the calorific value of petrol
B. the viscosity of lubricating oil
C. the knock resistance of petrol
D. the ignition quality of diesel fuel
View answer and explanation
Correct Option: D
A higher cetane number means a shorter ignition delay. The octane number rates petrol against knock.
Q163Mechanical Engineering (SSC JE)
Easy
The approximate stoichiometric air-fuel ratio for petrol is
A. 40 : 1
B. 25 : 1
C. 5 : 1
D. 14.7 : 1
View answer and explanation
Correct Option: D
About 14.7 kg of air is needed to burn 1 kg of petrol completely.
Q164Mechanical Engineering (SSC JE)
Hard
An engine develops 30 kW brake power while consuming fuel at 0.002 kg/s of calorific value 42 000 kJ/kg. The brake thermal efficiency is about
A. 50 percent
B. 28 percent
C. 35.7 percent
D. 42 percent
View answer and explanation
Correct Option: C
Heat supplied = 0.002 × 42 000 = 84 kW. η = 30/84 = 0.357.
Q165Mechanical Engineering (SSC JE)
Easy
In a diesel engine, the fuel is ignited by
A. a spark plug
B. the heat of compressed air
C. the exhaust gas
D. a glow plug in all conditions
View answer and explanation
Correct Option: B
Air is compressed to high temperature and the injected fuel self-ignites, which is why it is called a compression ignition engine.
Q166Mechanical Engineering (SSC JE)
Medium
The compression ratio of a typical compression ignition engine is in the range of
A. 4 to 6
B. 6 to 10
C. 30 to 40
D. 14 to 22
View answer and explanation
Correct Option: D
SI engines run at 6 to 10 to avoid knock, while CI engines need a much higher ratio to reach the self-ignition temperature.
Q167Mechanical Engineering (SSC JE)
Easy
A Carnot refrigerator works between 250 K and 300 K. Its COP is
A. 1.2
B. 5
C. 0.2
D. 6
View answer and explanation
Correct Option: B
COP = TL/(TH − TL) = 250/50 = 5.
Q168Mechanical Engineering (SSC JE)
Easy
One ton of refrigeration is equal to about
A. 7 kW
B. 0.35 kW
C. 3.5 kW
D. 1 kW
View answer and explanation
Correct Option: C
1 TR = 211 kJ/min = 3.517 kW, the rate of heat removal needed to freeze one tonne of water at 0 °C in 24 hours.
Q169Mechanical Engineering (SSC JE)
Easy
In a simple vapour compression refrigeration cycle, the refrigerant enters the compressor as
A. subcooled liquid
B. dry saturated or slightly superheated vapour
C. wet vapour with 50 percent dryness
D. saturated liquid
View answer and explanation
Correct Option: B
Liquid entering the compressor would damage the valves, so the vapour is kept dry.
Q170Mechanical Engineering (SSC JE)
Easy
The dew point temperature of air is the temperature at which
A. the dry bulb and wet bulb temperatures differ most
B. the humidity ratio is zero
C. water boils at atmospheric pressure
D. the air becomes saturated when cooled at constant pressure
View answer and explanation
Correct Option: D
On cooling below the dew point, vapour starts to condense.
Q171Mechanical Engineering (SSC JE)
Easy
The dry bulb and wet bulb temperatures of air are equal when the relative humidity is
A. 75 percent
B. 100 percent
C. 50 percent
D. 0 percent
View answer and explanation
Correct Option: B
In saturated air there is no evaporation from the wet bulb, so it reads the same as the dry bulb.
Q172Mechanical Engineering (SSC JE)
Medium
In a vapour absorption refrigeration system, the compressor of the vapour compression system is replaced by
A. a second condenser
B. an expansion valve
C. an absorber, a pump and a generator
D. a turbine
View answer and explanation
Correct Option: C
The refrigerant is absorbed in a solvent, pumped as a liquid and then driven off by heat in the generator, which uses much less work.
Q173Mechanical Engineering (SSC JE)
Easy
An economiser in a steam power plant is used to heat
A. the cooling water by the exhaust steam
B. the combustion air by the steam
C. the steam by the flue gases
D. the feed water by the flue gases
View answer and explanation
Correct Option: D
It recovers heat from the exit flue gases and raises boiler efficiency.
Q174Mechanical Engineering (SSC JE)
Easy
A Babcock and Wilcox boiler is a
A. fire tube boiler
B. water tube boiler
C. electric boiler
D. vertical fire tube boiler
View answer and explanation
Correct Option: B
Water flows in the tubes and the hot gases pass around them, which suits high pressures and large capacities.
Q175Mechanical Engineering (SSC JE)
Easy
The Parsons turbine is a
A. simple impulse turbine
B. reaction turbine
C. gas turbine
D. velocity compounded impulse turbine
View answer and explanation
Correct Option: B
The Parsons design has fixed and moving blades with a pressure drop in both. The De Laval turbine is an impulse turbine.
Q176Mechanical Engineering (SSC JE)
Easy
The main function of the condenser in a steam power plant is to
A. increase the boiler pressure
B. maintain a low back pressure so that more work is obtained from the turbine
C. dry the steam
D. supply hot water to the economiser
View answer and explanation
Correct Option: B
A low exhaust pressure gives a larger enthalpy drop in the turbine, and the condensate is reused as feed water.
Q177Mechanical Engineering (SSC JE)
Easy
In a nuclear reactor, the moderator is used to
A. slow down fast neutrons
B. absorb excess neutrons
C. remove heat from the core
D. shield against radiation
View answer and explanation
Correct Option: A
Slow (thermal) neutrons are far more likely to cause fission in U-235. Control rods absorb neutrons and the coolant removes heat.
Q178Mechanical Engineering (SSC JE)
Easy
A gas turbine plant works on the
A. Stirling cycle
B. Brayton cycle
C. Otto cycle
D. Rankine cycle
View answer and explanation
Correct Option: B
The Brayton cycle consists of isentropic compression, constant pressure heat addition, isentropic expansion and constant pressure heat rejection.
Q179Mechanical Engineering (SSC JE)
Hard
A hydroelectric plant has a flow of 10 m³/s under a head of 50 m with an overall efficiency of 90 percent. The power output is about
A. 4.41 MW
B. 4.9 MW
C. 0.49 MW
D. 44.1 MW
View answer and explanation
Correct Option: A
P = η ρ g Q H = 0.9 × 1000 × 9.81 × 10 × 50 = 4.41 × 10⁶ W.
Q180Mechanical Engineering (SSC JE)
Easy
The dryness fraction of dry saturated steam is
A. 0
B. 1
C. greater than 1
D. 0.5
View answer and explanation
Correct Option: B
The dryness fraction x is the mass of dry vapour divided by the total mass. It is 1 for dry saturated steam and 0 for saturated liquid.
Q181Mechanical Engineering (SSC JE)
Easy
A riser in a casting mould is provided to
A. allow the pattern to be withdrawn
B. cool the casting faster
C. increase the mould strength
D. feed molten metal to the casting as it shrinks on solidification
View answer and explanation
Correct Option: D
The riser is the last part to solidify and supplies liquid metal, which prevents shrinkage cavities in the casting.
Q182Mechanical Engineering (SSC JE)
Easy
The shrinkage allowance is given on a pattern so that
A. the mould cavity is sealed
B. the pattern can be easily removed from the mould
C. the casting has the correct size after it cools
D. the casting is made lighter
View answer and explanation
Correct Option: C
The pattern is made slightly larger than the finished casting to offset the contraction of metal during cooling.
Q183Mechanical Engineering (SSC JE)
Easy
TIG welding uses a non-consumable electrode made of
A. copper
B. mild steel
C. aluminium
D. tungsten
View answer and explanation
Correct Option: D
Tungsten has a very high melting point. An inert gas such as argon protects the weld pool.
Q184Mechanical Engineering (SSC JE)
Hard
A workpiece of 50 mm diameter turns at 400 rpm on a lathe. The cutting speed is about
A. 20 m/min
B. 125.7 m/min
C. 6.28 m/min
D. 62.8 m/min
View answer and explanation
Correct Option: D
V = πDN/1000 = π × 50 × 400 / 1000 = 62.8 m/min.
Q185Mechanical Engineering (SSC JE)
Medium
In up milling (conventional milling), the chip thickness is
A. maximum at the start and zero at the end
B. zero at the start of the cut and maximum at the end
C. zero throughout the cut
D. constant throughout the cut
View answer and explanation
Correct Option: B
The cutter rotates against the feed, so each tooth starts with a thin chip that thickens as it leaves the work.
Q186Mechanical Engineering (SSC JE)
Easy
Hot working of metals is done above
A. the eutectic temperature
B. the melting temperature
C. the room temperature
D. the recrystallisation temperature
View answer and explanation
Correct Option: D
Above this temperature, new strain-free grains form as the metal is deformed, so it does not strain harden.
Q187Mechanical Engineering (SSC JE)
Easy
In blanking, the piece punched out of the sheet is
A. the scrap
B. the required product
C. a lubricant
D. the die
View answer and explanation
Correct Option: B
In punching, by contrast, the punched piece is waste and the sheet with holes is the product.
Q188Mechanical Engineering (SSC JE)
Easy
Cold working a metal generally
A. melts the grain boundaries
B. decreases its strength
C. increases its strength and hardness and decreases its ductility
D. increases its ductility
View answer and explanation
Correct Option: C
Strain hardening raises the yield strength but exhausts the ability of the metal to deform further.
Q189Mechanical Engineering (SSC JE)
Easy
Taylor’s tool life equation is
A. V / T = C
B. V = C Tⁿ
C. V + T = C
D. V Tⁿ = C
View answer and explanation
Correct Option: D
V is the cutting speed, T the tool life and n and C are constants for the tool and work material.
Q190Mechanical Engineering (SSC JE)
Easy
Case hardening is done to obtain
A. a hard surface with a tough core
B. a soft surface with a hard core
C. a uniformly hard component
D. a uniformly soft component
View answer and explanation
Correct Option: A
Carburising, nitriding or cyaniding adds hardness to the surface layer of a low carbon steel part.
Q191Mechanical Engineering (SSC JE)
Easy
Sintering in powder metallurgy is
A. melting the powder completely
B. pressing the powder in a die
C. blending the powders
D. heating the compacted powder below its melting point to bond the particles
View answer and explanation
Correct Option: D
Atoms diffuse across particle contacts at high temperature, which gives strength to the compact.
Q192Mechanical Engineering (SSC JE)
Easy
Increasing the rake angle of a cutting tool generally
A. makes the tool more brittle and stronger
B. increases the cutting force
C. reduces the cutting force
D. has no effect on the cutting force
View answer and explanation
Correct Option: C
A larger rake angle shears the chip more easily, but a very large angle weakens the cutting edge.
Q193Mechanical Engineering (SSC JE)
Easy
The angle of friction is equal to
A. the angle of contact
B. twice the angle of repose
C. the angle of repose
D. the angle of incidence
View answer and explanation
Correct Option: C
tan φ = μ, and the angle of repose, at which a body is just about to slide, has the same value.
Q194Mechanical Engineering (SSC JE)
Easy
A body of mass 2 kg moves at 4 m/s. Its kinetic energy is
A. 8 J
B. 4 J
C. 16 J
D. 32 J
View answer and explanation
Correct Option: C
KE = ½mv² = 0.5 × 2 × 16 = 16 J.
Q195Mechanical Engineering (SSC JE)
Easy
The centre of gravity of a triangle from its base is at a distance of
A. one-half of its height
B. one-third of its height
C. one-fourth of its height
D. two-thirds of its height
View answer and explanation
Correct Option: B
The centroid lies at the intersection of the medians, at h/3 from the base.
Q196Mechanical Engineering (SSC JE)
Easy
A projectile has the maximum horizontal range on level ground when its angle of projection is
A. 30°
B. 45°
C. 60°
D. 90°
View answer and explanation
Correct Option: B
R = u² sin 2θ / g is largest when sin 2θ = 1, that is, θ = 45°.
Q197Mechanical Engineering (SSC JE)
Easy
In a vernier caliper, 50 vernier divisions coincide with 49 main scale divisions, and one main scale division is 1 mm. The least count is
A. 0.02 mm
B. 0.05 mm
C. 0.1 mm
D. 0.01 mm
View answer and explanation
Correct Option: A
LC = 1 MSD − 1 VSD = 1 − 49/50 = 0.02 mm.
Q198Mechanical Engineering (SSC JE)
Easy
In limits and fits, tolerance is
A. the difference between the upper and lower limits of a dimension
B. the difference between the sizes of mating parts
C. the clearance between two parts
D. the nominal size of a part
View answer and explanation
Correct Option: A
It is the permissible variation in a dimension, whereas allowance is the intended difference between mating parts.
Q199Mechanical Engineering (SSC JE)
Medium
The Economic Order Quantity (EOQ) is given by
A. 2DS / H
B. √(DS / 2H)
C. √(2DS / H)
D. √(2H / DS)
View answer and explanation
Correct Option: C
D is annual demand, S the ordering cost per order and H the holding cost per unit per year.
Q200Mechanical Engineering (SSC JE)
Easy
Stainless steel contains a minimum chromium content of about
A. 11 percent
B. 5 percent
C. 25 percent
D. 2 percent
View answer and explanation
Correct Option: A
About 10.5 to 11 percent chromium forms a thin self-healing chromium oxide layer, which resists corrosion.

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