(A): When a wave goes from one medium to other, average power transmitted by the wave may change.
(R): Due to a change in the medium, amplitude, speed, wavelength and frequency of the wave may change. A) Both 'A' and 'R' are true and 'R' is the correct, explanation of 'A'. B) Both 'A' and 'R' are true and 'R' is not the correct explanation of 'A' C) A' is true and 'R' is false D Both 'A' and 'R' are false

Options

A. Both 'A' and 'R' are true and 'R' is the correct, explanation of 'A'.
B. Both 'A' and 'R' are true and 'R' is not the correct explanation of 'A'
C. A' is true and 'R' is false
D. Both 'A' and 'R' are false

Answer

To solve the question, we need to analyze both the assertion (A) and the reason (R) provided:

**Assertion (A):** When a wave goes from one medium to another, the average power transmitted by the wave may change.

**Reason (R):** Due to a change in the medium, amplitude, speed, wavelength, and frequency of the wave may change.

### Step-by-Step Solution:

1. **Understanding the Assertion (A):**
- When a wave travels from one medium to another, it can experience changes in its properties. The average power transmitted by the wave is given by the formula:
\[ P = \frac{1}{2} \mu A^2 \omega^2 v \]
where \( \mu \) is the linear density of the medium, \( A \) is the amplitude, \( \omega \) is the angular frequency, and \( v \) is the wave velocity.
- Since the medium changes, the linear density \( \mu \) and the wave velocity \( v \) can change, which can lead to a change in average power \( P \). Thus, assertion (A) is **true**.

2. **Understanding the Reason (R):**
- The reason states that due to a change in the medium, the amplitude, speed, wavelength, and frequency of the wave may change.
- While it is true that the amplitude, speed, and wavelength can change when a wave enters a different medium, the frequency of the wave remains constant. The frequency is determined by the source of the wave and does not change when transitioning between media.
- Therefore, the statement in reason (R) is **false** because it incorrectly claims that frequency changes.

3. **Conclusion:**
- Since assertion (A) is true and reason (R) is false, the correct option is **C**: "A is true and R is false."