Question

The speed of electromagnetic wave in any material medium does not depend on.

• A. Upon its wavelength
• B. Upon its frequency
• C. Upon its intensity
• D. Upon its permittivity

Hint:

The speed of an electromagnetic wave in a medium depends on its permittivity and permeability, but not on its intensity.

Answer 1

The Correct Option is C

Step 1: Speed of electromagnetic waves.
The speed of an electromagnetic wave in a material medium is given by the formula: \[ v = \frac{c}{\sqrt{\epsilon_r \mu_r}} \] where \( c \) is the speed of light in a vacuum, \( \epsilon_r \) is the relative permittivity, and \( \mu_r \) is the relative permeability of the medium. The wave’s speed depends on the medium’s properties, not its frequency, wavelength, or intensity.
Step 2: Elimination of options.
- (A) Upon its wavelength: The speed of light is related to its wavelength and frequency through the equation \( v = \lambda f \). Wavelength is inversely proportional to frequency in a given medium.
- (B) Upon its frequency: The frequency of an electromagnetic wave is related to its speed in a particular medium.
- (C) Upon its intensity: The intensity of the wave does not affect the speed of light in the medium. Intensity is related to the amplitude of the wave, not its velocity.
- (D) Upon its permittivity: The speed of light depends on the permittivity of the medium.
Conclusion: The speed of the electromagnetic wave does not depend on its intensity.