Physics questions with answers

2,629 multiple-choice questions. Open any question for its answer and explanation.

Questions asked in State PSC and UPSC prelims, by topic. Each topic also has notes to read.

Read the notes: Mechanics →

1. A railway wagon (open at the top) of mass M₁ is moving with speed v₁ along a straight track. As a result of rain, after some time it gets partially filled with water so that the mass of the wagon becomes M₂ and speed becomes v₂. Taking the rain to be falling vertically and water stationary inside the wagon, the relation between the two speeds v₁ and v₂ is :Asked in UPSC NDA 1 2023
2. Sand falls vertically on a conveyor belt at a rate of 0·1 kg/s. In order to keep the belt moving at a uniform speed of 2 m/s, the force required to be applied on the belt is :Asked in UPSC NDA 1 2023
3. Let there be an object having some chemicals in it. It starts moving with a uniform velocity v and a chemical reaction starts happening. In this case, which of the following statement/s is/ are correct ? 1. Chemical reactions happening in the system cannot change the velocity v of the center of mass of the object. 2. Chemical reactions happening in the system cannot change the kinetic energy of the particles inside with respect to the center of mass of object. Select the correct answer using the code given below :Asked in UPSC NDA 2 2019
4. Fundamental laws of physics requireAsked in UPSC NDA 2 2021
5. A bullet of mass 10 g is horizontally fired with velocity 300 m s$^{-1}$ from a pistol of mass 1 kg. What is the recoil velocity of the pistol?Asked in UPSC NDA 2 2022
6. If the linear momentum of a moving object changes by two times, then its kinetic energy will change by a factor ofAsked in UPSC CAPF 2022
7. Which one of the following conservation laws is a consequence of the Newton's third law of motion ?Asked in UPSC CAPF 2023
8. Rocket works on the principle of the following:Asked in UPPSC Upper Mains 2014
9. Assertion (A): A man standing on a completely frictionless surface can propel himself by whistling. Reason (R): If no external force acts on a system, its momentum cannot change.Asked in UPPCS Prelims 2000
10. The jet plane engine works on the principle of:Asked in APPSC Draughtman 2008
11. A bullet of mass 20 g is horizontally fired with a velocity 150 m/s from a pistol of mass 2 kg. The recoil velocity of the pistol will beAsked in School Lecturer (Sanskrit Edu.) 2020
12. A girl of mass 40 kg jumps with horizontal velocity of 6 m/s onto a stationary cart with frictionless wheels. If the mass of cart is 4 kg, then the final velocity of system will be (No external force is working in horizontal direction) -Asked in School Lecturer (Sanskrit Edu.) 2022 4 2022
13. Rocket works on which of the following principles?Asked in RO ARO Mains 2021
14. A sphere of radius 100 cm is cut by a plane at a distance of h from its center, thereby breaking this sphere into two different pieces. The cumulative surface area of these two pieces is 25% more than that of the sphere. What is the value of h?Asked in GPSC Prelims CSP 1 2022
15. Following are general statements about water drops. (a) Surface tension is responsible for the spherical shape of the water drops. (b) Even in the absence of gravitation, water drops have spherical shape. (c) Formation of water drops occurs, if mass of the water is stretched. Which of the above statement/statements is/are correct?Asked in MPSC CS Prelims 2013
16. A spring of spring constant k is cut into two equal halves. The spring constant of each half is nowAsked in WBPSC CS Prelims 2021
17. Bulk Modulus for a perfectly rigid body isAsked in ukpsc 2025 2025
18. If the principal stresses in a plane stress problem, are $\sigma_1 = 100$ MPa, $\sigma_2 = 40$ MPa, the magnitude of the maximum shear stress in MPa will be - (5) Question not attemptedAsked in Assistant Eng. (Mechanical) Competitive Examination, 2023
19. The Young’s modulus of elasticity of steel is 210 GPa, and the Poisson’s ratio is 0.29. The shear modulus will be : - (5) Question not attemptedAsked in Assistant Eng. (Mechanical) Competitive Examination, 2023
20. Maximum shear stress developed on the surface of a solid circular shaft under pure torsion is 240 MPa. If the shaft diameter is doubled, the maximum shear stress developed corresponding to the same torque will be : - (5) Question not attemptedAsked in Assistant Eng. (Mechanical) Competitive Examination, 2023
21. A cylindrical rod of length, l and diameter, d, is rigidly fixed at its upper end and hangs vertically. The elongation produced in the rod due to its total self weight, W is: - (5) Question not attempted Where A is area of cross-section of cylindrical rod and E is modulus of elasticity.Asked in Assistant Eng. (Mechanical) Competitive Examination, 2023
22. A gradually varying cross-section tapering bar with diameter of the end sections being d1 and d2 and a bar having uniform cross section with diameter d have the same length L and subjected to the same axial pull P and are made of same material, then both the bars will have the same extension if d is equal to : - (5) Question not attemptedAsked in Assistant Eng. (Mechanical) Competitive Examination, 2023
23. A simply supported beam of constant flexural rigidity and length 2L carries a concentrated load P at its mid span and the maximum deflection under the load is δ. A cantilever beam of the same flexural rigidity and length L is subjected to load P at its free end. Determine the relation between the deflection at free end of the cantilever with δ. - (5) Question not attemptedAsked in Assistant Eng. (Mechanical) Competitive Examination, 2023
24. A steel member of area of cross section 1000 mm², having a length of 1 m is subjected to an axial compressive load of 10 kN. Assuming the case of pure compression in the member, the axial deflection is given by: (Take E = 200 GPa) - Question not attemptedAsked in Assistant Eng. (Mechanical) Competitive Examination, 2023
25. The S-N curve for steel becomes asymptotic nearly at - Question not attemptedAsked in Assistant Eng. (Mechanical) Competitive Examination, 2023