Physics Set 18 FAQs

1. About what percentage of the total global carbon is found in the oceans?

2. The maximum number of electrons that can be accommodated in the outermost shell of an atom is:

3. The most abundant isotope of hydrogen in nature is:

4. A temperature of 27 °C on the Kelvin scale is:

5. Consider the following statements: (I) An object moving along a straight line with constant speed is in uniform linear motion. (II) An object in uniform linear motion covers equal distances in equal intervals of time. (III) An object in non-uniform linear motion covers equal distances in equal intervals of time. Which of the above is/are correct?

6. A concave lens has a focal length of 25 cm. Its power is:

7. Between two consecutive marks of a spring balance, 2 N apart, there are 5 equal divisions. The smallest weight it can read is:

8. The fixed point about which a lever rotates is called the:

9. Consider the following pairs: (I) Electric current – ampere (II) Amount of substance – mole (III) Luminous intensity – kelvin Which of the pairs given above is/are correctly matched?

10. Consider the following statements about the speed of sound in air: (I) It increases with an increase in temperature. (II) It increases with an increase in humidity. (III) It depends on the frequency of the source. Which of the above is/are correct?

11. Plastic foams are good insulators mainly because they contain:

12. The mass of an electron is:

13. Assertion (A): Appliances in a domestic circuit are connected in parallel. Reason (R): Parallel connection ensures that each appliance has the same potential difference. Choose the correct statement:

14. A negative sign in the value of magnification produced by a spherical mirror indicates that the image is:

15. Consider the following pairs: (I) Sound wave – Mechanical wave (II) Light wave – Mechanical wave (III) Sound wave – Longitudinal wave Which of the pairs given above is/are correctly matched?

16. The commercial unit of electrical energy is:

17. Which of the following is not a mode of heat transfer?

18. Niels Bohr proposed his model of the atom in:

19. If the velocity of a vehicle becomes three times its original value, its kinetic energy becomes:

20. Which of the following planets is mostly made of gas and ice?

21. One atmosphere is equal to:

22. With respect to the displacement plot, the acceleration plot in SHM has a phase difference of:

23. A sonar signal returns from the sea bed after 2.4 s. If the speed of sound in seawater is 1500 m s⁻¹, the depth of the sea bed is:

24. Sound waves with frequency above 20 kHz are called:

25. The refreezing of water above a wire that has passed through an ice slab is called:

26. Among the following alloys, the highest resistivity at 20 °C is of:

27. 1 mm is equal to:

28. The walls of a Dewar flask are coated with:

29. Consider the following pairs: (I) Electric bulb – Electrical energy to light energy (II) Ringing bell – Mechanical energy to sound energy (III) Electric water heater – Electrical energy to mechanical energy Which of the pairs given above is/are correctly matched?

30. The force with which the Earth pulls an object towards itself is called its: