Physics Set 25 FAQs

1. A steel rod is prevented from expanding while its temperature rises by 20 K. If αl = 1.2 × 10⁻⁵ K⁻¹ and Young's modulus Y = 2 × 10¹¹ N m⁻², the thermal stress developed is:

2. Consider the following statements: (I) Magnetic field lines are closed curves. (II) The field lines are crowded where the magnetic field is stronger. (III) Two magnetic field lines can cross each other near the poles. Which of the above is/are correct?

3. In traditional Indian measurement, 'angula' refers to:

4. With the potential energy taken as zero at infinite separation, the gravitational potential energy of two particles of masses m₁ and m₂ separated by a distance r is:

5. According to Maxwell's electromagnetic theory, an accelerated charged particle emits:

6. The slope of a velocity-time graph gives:

7. The SI unit of resistance is:

8. The lens formula relating object distance u, image distance v and focal length f is:

9. Excess atmospheric CO₂ absorbed by the oceans makes sea water more:

10. Work done against which of the following forces does not result in storage of energy?

11. A freely suspended bar magnet comes to rest along the:

12. In the Northern Hemisphere, the shortest day occurs around:

13. Consider the following pairs: (I) Swing – Oscillatory motion (II) Merry-go-round – Circular motion (III) Eraser whirled on a thread – Oscillatory motion Which of the pairs given above is/are correctly matched?

14. Millikan concluded that the electrical charge on an oil droplet is always:

15. The day-night cycle is caused by the:

16. When the North pole of a bar magnet is brought near the North pole of a compass needle, the needle:

17. In SHM, the speed of the particle is maximum at the:

18. Water seeps fastest through:

19. Two point masses of 20 kg each are separated by 0.5 m. Taking G = 6.67 × 10⁻¹¹ N m² kg⁻², their gravitational potential energy is:

20. Huygens' early pendulum clocks could gain or lose about how much time each day?

21. The mechanical energy of an object is conserved if:

22. Among the following, the material with the lowest resistivity at 20 °C is:

23. Mission LiFE, an India-led global initiative, was introduced at the United Nations Climate Change Conference in:

24. The V–I graph of a nichrome wire is:

25. Consider the following statements about a uniform hollow spherical shell: (I) The force on a point mass outside it is as if the entire mass of the shell were at its centre. (II) The force on a point mass inside it is zero. (III) It shields a body inside it from the gravitational pull of outside bodies. Which of the above is/are correct?

26. Surfaces of which colour absorb and emit radiant energy best?

27. The splitting of white light into its component colours is called:

28. The maximum acceleration of a particle in SHM with amplitude A and angular frequency ω is:

29. Consider the following pairs: (I) Electric iron – Heating effect of current (II) Electromagnet – Magnetic effect of current (III) Electric bell – Heating effect of current Which of the pairs given above is/are correctly matched?

30. The electric potential difference between two points is defined as the work done to move: