Question

When light is reflected from an optically rarer medium:

• A. its phase remains unchanged but its frequency increases
• B. both its phase and frequency remain unchanged
• C. its phase changes by \( \pi \) but the frequency remains unchanged
• D. its phase remains the same but the frequency decreases
• E. its phase changes by \( \frac{\pi}{2} \) but the frequency remains unchanged

Hint:

For light reflected from a rarer medium, the phase changes by \( \pi \), but the frequency of the light remains the same.

Answer 1

The Correct Option is B

Step 1: When light is reflected from an optically rarer medium, the frequency of the light remains unchanged, as the frequency of light does not depend on the medium. 
Step 2: However, the phase of the light changes by \( \pi \), as the reflection from a rarer medium results in a phase shift of \( \pi \). 
Step 3: Thus, both the phase and frequency of the light remain unchanged in the reflected wave.