Electromagnetic Waves Mock Test – Class 12 Physics

1. In Gauss's law for electricity mainly relates electric flux through a closed surface to

2. A set of four statements is written about the Maxwell framework.
Statement I: Charges are related to electric flux.
Statement II: Isolated magnetic poles are represented by non-zero net magnetic flux through a closed surface.
Statement III: A changing magnetic field can produce an electric field.
Statement IV: A changing electric field can produce a magnetic field.

3. A thermal camera forms images in darkness by detecting radiation emitted by warm objects. The electromagnetic region most directly involved is

4. A plane electromagnetic wave has the electric field . At fixed , the field varies with

5. A wave expression contains the phase . If the phase is to be dimensionless, the units of and should be

6. A basic wave record for an electromagnetic wave lists , , and . The blank in the relation is best filled by

7. Among the following, the pair most strongly associated with ionising electromagnetic radiation is

8. Radio waves are widely used for broadcasting and communication mainly because they

9. Study the table and select the row that is physically consistent.

10. A plane electromagnetic wave in vacuum has at a particular point and instant. Using , the magnetic field magnitude at that point and instant is

11. An electromagnetic wave has frequency . Its angular frequency is

12. A graph of versus and versus for the same plane wave shows that the magnetic curve has the same wavelength but much smaller numerical amplitude. The best explanation is that

13. Study the table for a plane electromagnetic wave in vacuum and select the row that is consistent with , taking .

14. A light sail in space is pushed very slightly by sunlight. The best explanation is that sunlight

15. Consider the following charge situations.
Statement I: A stationary charge produces an electric field.
Statement II: A steady moving charge produces electric and magnetic fields.
Statement III: An accelerated charge can produce electromagnetic waves.

16. Consider the following statements about energy in electromagnetic waves.
Statement I: The electric field of an electromagnetic wave stores energy.
Statement II: The magnetic field of an electromagnetic wave stores energy.
Statement III: Energy transport by an electromagnetic wave requires matter to vibrate along the path.

17. A claim says, "Since and have different units, the electric and magnetic parts of energy density cannot be equal in a plane wave." The claim is

18. A displacement current and a conduction current are compared only by their SI units. The suitable unit for both is

19. A graph-like description says: Region has the largest wavelength, Region has an intermediate wavelength, and Region has the smallest wavelength. If the three regions are radio waves, visible light, and X-rays, the correct assignment is

20. Assertion: Electromagnetic waves can travel through vacuum.
Reason: Their propagation is associated with time-varying electric and magnetic fields, not with vibrations of material particles.

21. A vacuum electromagnetic wave has instantaneous electric field . Taking , the instantaneous electric energy density is closest to

22. Use the arrangement described below. A plane electromagnetic wave moves horizontally toward the right. At one instant, the electric field is shown vertically upward. The magnetic field should be imagined

23. The atmosphere does not transmit all electromagnetic waves equally. This means that

24. A perfectly absorbing surface and a perfectly reflecting surface are exposed to the same beam of electromagnetic radiation. The radiation pressure is greater on the reflecting surface because

25. Assertion: The mutual connection between changing electric and magnetic fields helps explain electromagnetic waves.
Reason: A changing electric field can produce a magnetic field, and a changing magnetic field can produce an electric field.

26. A capacitor gap has electric flux . The maximum displacement current in the gap is closest to

27. Study the table for visible colours and select the row with the most suitable comparison.

28. Maxwell's prediction that electromagnetic waves travel with speed became especially important because the calculated value

29. An X-ray beam has wavelength in vacuum. Taking , its frequency is

30. Assertion: The original Ampere's circuital law becomes incomplete for a charging capacitor.
Reason: The choice of surface bounded by the same loop can give different enclosed conduction currents.

31. A plate of a capacitor receives charge at a steady rate so that increases uniformly with time. In the ideal parallel-plate region, the graph of electric flux versus charge should be

32. A source emits electromagnetic radiation during a nuclear transition inside an unstable nucleus. The radiation is most likely

33. A microwave oven heats food effectively because microwaves can transfer energy mainly to

34. In a plane wave, and are plotted against time at a fixed point. The curve reaches exactly when the curve reaches . This observation confirms that

35. A radiation has wavelength . Compared with the approximate visible range , this radiation is most likely

36. X-rays are useful in medical imaging mainly because they

37. Use the situation below.

For the same boundary path, the reason both surfaces can give the same magnetic circulation after Maxwell's correction is that

38. A plane electromagnetic wave is written as and . The wave propagates along

39. A property common to all electromagnetic waves in vacuum is that they

40. In a vacuum plane electromagnetic wave, using , , and , the electric energy density becomes

41. If the frequency of an electromagnetic wave in vacuum is doubled, its wavelength becomes

42. A proposed plane wave is written as and . The phase suggests propagation along , but the field directions make the proposal

43. A field record gives the instantaneous electric field at a point in a plane electromagnetic wave in vacuum. The instantaneous magnetic field magnitude at the same point and instant is

44. A vacuum region contains a uniform electric field whose magnitude is increasing with time. No free charges are crossing the region. The current-like quantity that may still be associated with the region is

45. A capacitor is being charged, and a surface through the plate gap has but . Another surface with the same boundary cuts the wire. Under ideal conditions, the wire surface should have

46. Displacement current is introduced to represent the current-like effect produced by

47. A radio transmitting antenna works because charges in it are made to

48. A claim says, "An electromagnetic wave cannot exert any effect on matter because it has no material particles." The claim is

49. In a table of Maxwell-equation meanings, the entry "net magnetic flux through a closed surface" should be paired with

50. In a charging capacitor, the current in the connecting wire is . Under ideal conditions, the displacement current between the plates is