Two waves of same frequency and intensity superimpose on each other in opposite phases. After the superposition the intensity and frequency of waves will.

Options

A. 1. increase
B. 2. decrease
C. 3. remains constant
D. 4. becomes zero

Explanation

To solve the question regarding the superposition of two waves of the same frequency and intensity that are in opposite phases, we can follow these steps:

### Step 1: Understand the Concept of Superposition
When two waves meet, they superimpose, meaning they combine to form a new wave. The principle of superposition states that the resultant displacement at any point is the sum of the displacements of the individual waves.

**Hint:** Remember that superposition can lead to constructive or destructive interference depending on the phase relationship of the waves.

### Step 2: Identify the Phase Relationship
In this case, the two waves are in opposite phases. This means that when one wave has a positive displacement, the other wave has a negative displacement of the same magnitude.

**Hint:** Opposite phases imply that the waves will cancel each other out when they meet.

### Step 3: Analyze the Resultant Amplitude
Since the waves are in opposite phases, their amplitudes will cancel each other out. If the amplitude of each wave is A, the resultant amplitude (R) after superposition will be:
\[ R = A - A = 0 \]

**Hint:** Think about how two equal forces acting in opposite directions result in a net force of zero.

### Step 4: Determine the Resultant Intensity
The intensity (I) of a wave is proportional to the square of its amplitude:
\[ I \propto R^2 \]
Since the resultant amplitude is zero, the intensity will also be:
\[ I = 0^2 = 0 \]

**Hint:** Recall that intensity is related to the amplitude squared; if amplitude is zero, intensity must also be zero.

### Step 5: Consider the Frequency
The frequency of a wave is a property that does not change due to superposition. Since both waves have the same frequency and are simply interfering, the frequency of the resultant wave remains the same as that of the individual waves.

**Hint:** Frequency is a characteristic of the wave itself and is not affected by the amplitude or intensity.

### Conclusion
After the superposition of the two waves, the resultant intensity is zero, and the frequency remains unchanged. Therefore, the final answer is that the intensity becomes zero, and the frequency remains the same.

### Final Answer
- Intensity: 0
- Frequency: Same as the original waves

**Correct Option:** D. Intensity becomes zero, frequency remains the same.