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Electromagnetic Waves question

2023 · 29 Jan · Shift 1 · Q59
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  5. /2023 · 29 Jan · Shift 1 · Q59

Electromagnetic Waves question

2023 · 29 Jan · Shift 1 · Q59

JEE MainPhysicsElectromagnetic WavesMCQ+4 / −1
Which of the following are true? A. Speed of light in vacuum is dependent on the direction of propagation. B. Speed of light in a medium is independent of the wavelength of light. C. The speed of light is independent of the motion of the source. D. The speed of light in a medium is independent of intensity. Choose the correct answer from the options given below:
  1. A
    B and D only
  2. B
    B and C only
  3. C
    A and C only
  4. D
    C and D only
View written solutionFree

Correct answer: D

  1. Check statement A: Speed of light in vacuum is dependent on the direction of propagation.

    In vacuum, the speed of light is a universal constant: c=3×108 m/sc = 3 \times 10^8\ \text{m/s}c=3×108 m/s It is the same in all directions. Hence, this statement is false.

  2. Check statement B: Speed of light in a medium is independent of the wavelength of light.

    In a medium, v=cnv = \frac{c}{n}v=nc​ where nnn is the refractive index. In general, nnn depends on wavelength due to dispersion, so speed in a medium depends on wavelength.

    Therefore, statement B is false.

  3. Check statement C: The speed of light is independent of the motion of the source.

    According to Einstein’s special theory of relativity, the speed of light in vacuum is independent of the motion of the source or observer.

    So statement C is true.

  4. Check statement D: The speed of light in a medium is independent of intensity.

    For ordinary linear media, the speed of light in a medium depends on refractive index and not on intensity.

    Thus statement D is true.

  5. Conclusion:

    • A: False
    • B: False
    • C: True
    • D: True

    Therefore, the correct combination is: C and D only\boxed{\text{C and D only}}C and D only​

  6. Match with options:

    Option D = C and D only.

Hence, the correct answer is Option D.

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