Electromagnetic Waves Mock Test – Class 12 Physics

1. Read the situation below and answer the question.

The grouping should be corrected because

2. A statement says, "In an electromagnetic wave, and are in phase, so they must be parallel." The statement is

3. Read the situation below and answer the question.

The choice is reasonable mainly because

4. An electromagnetic wave in vacuum has wavelength , while another has wavelength . The frequency of the second wave is

5. A claim says, "All electromagnetic waves are dangerous in the same way because they all carry energy." The claim is

6. A wave in vacuum has . Its frequency lies at

7. A comparison asks why the same electromagnetic family can include both communication waves and medical ionising radiation. The best answer is that

8. A changing electric field in one region and a changing magnetic field in a neighbouring region are part of a travelling disturbance. The best reason this disturbance can continue through vacuum is that

9. A claim says, "During capacitor charging, no conduction current crosses the gap; therefore, the magnetic field in the capacitor region must be absent." The best evaluation is that the claim is

10. A wave has and . The speed calculated from these data is

11. The electric and magnetic fields in an electromagnetic wave should not be imagined as

12. A vacuum electromagnetic wave has electric-field amplitude . With , the magnetic-field amplitude is

13. A wave has and another has , both in vacuum. The frequency of the wave is

14. A charging capacitor has plate area and charge increasing according to . For an ideal parallel-plate capacitor in vacuum, the displacement current between the plates is

15. Assertion: Gamma rays have higher frequency than radio waves.
Reason: In vacuum, electromagnetic waves with shorter wavelength have higher frequency.

16. A comparison between mechanical waves and electromagnetic waves is made. The feature that belongs specifically to electromagnetic waves in vacuum is

17. X-rays and gamma rays are both high-frequency electromagnetic radiations, but in classification they are often distinguished mainly by

18. 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

19. In a capacitor experiment, the plate area is doubled while the charge on the plates remains the same. For the ideal relation and , the electric flux through the plate area

20. Assertion: X-rays require careful use in medical imaging.
Reason: X-rays are ionising electromagnetic radiation and can interact strongly with matter.

21. Consider the following statements about atmospheric propagation.
Statement I: The atmosphere has wavelength ranges through which radiation passes more easily.
Statement II: Ozone absorbs much harmful ultraviolet radiation.
Statement III: Infrared absorption by atmospheric molecules has no heating relevance.

22. A mixed spectrum table is shown below.

The best judgement about the table is that

23. Consider the following statements about displacement current.
Statement I: It can exist in a vacuum region if electric flux changes with time.
Statement II: It is always due to free electrons crossing a metallic conductor.
Statement III: It can contribute to magnetic-field circulation.

24. A claim says, "A charge moving uniformly in a straight line is enough to radiate electromagnetic waves continuously." The best evaluation is that the claim is

25. Consider the following statements about the corrected Ampere-Maxwell law.
Statement I: It contains the term .
Statement II: It removes the surface-choice inconsistency in a charging capacitor.
Statement III: It says that displacement current is ordinary charge flow through a vacuum gap.

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

27. For an ideal charging parallel-plate capacitor, . Using the displacement-current formula, the relation between and the conduction current is

28. A communication signal is sent as a radio wave of frequency . Taking , its wavelength in vacuum is

29. If a region has no conduction current but its electric flux changes with time, the Maxwell-equation idea that can still connect it to magnetic field is

30. The corrected Ampere-Maxwell law for a surface bounded by a closed path is

31. Consider the following statements about changing fields.
Statement I: A changing magnetic field can produce an electric field.
Statement II: A changing electric field can produce a magnetic field.
Statement III: A material medium is compulsory for these field interactions to exist.

32. A radiation has photon energy at frequency . Another radiation has frequency . According to , the photon energy of the second radiation is

33. Consider the following statements about a charging capacitor.
Statement I: Conduction current flows in the connecting wires.
Statement II: The dielectric gap between the plates has ordinary charge flow just like a metallic wire.
Statement III: The electric field between the plates changes as charge accumulates on the plates.

34. Sunlight warms a surface on Earth after travelling through space. This is possible because electromagnetic waves

35. Consider the following statements about electromagnetic-wave propagation.
Statement I: The wave can travel through vacuum.
Statement II: The wave carries energy in its electric and magnetic fields.
Statement III: The wave requires a material medium because it is a mechanical vibration.

36. A material glows visibly when ultraviolet radiation falls on it, while a warm human body is viewed by a thermal camera. The first and second effects involve

37. For electric field , two commonly used units are

38. Consider the following statements about the electromagnetic spectrum.
Statement I: It is a continuous range of electromagnetic radiation.
Statement II: The boundaries between neighbouring regions are perfectly sharp natural lines.
Statement III: All regions of the spectrum travel with speed in vacuum.

39. A plane electromagnetic wave is travelling along . Its electric field is along . The magnetic field must be along

40. Gamma rays are used in some cancer-treatment methods mainly because they can

41. A note says: "Electromagnetic waves in vacuum differ in and , but the value is common to all of them." This note is

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

43. A plane electromagnetic wave has along and along . The direction of propagation is along

44. Match each Maxwell equation idea with its qualitative meaning.

45. Microwave radiation used in radar and satellite links is commonly generated by

46. A radiation has short wavelength, high photon energy, strong penetration, and requires careful shielding in medical use. It is most likely

47. Consider the following statements about ultraviolet radiation.
Statement I: It has higher frequency than visible light.
Statement II: It has longer wavelength than infrared radiation.
Statement III: It can cause fluorescence in some substances.

48. A comparison is made among radio waves, visible light, X-rays, and gamma rays in vacuum. The correct common feature is that all of them

49. A vacuum parallel-plate capacitor has plate area and charge . Taking , the electric field between the plates is

50. The most complete statement about electromagnetic waves in vacuum is that they