Three harmonic waves having equal frequency and same intensity `I_(0)` have phase angle`- phi, 0 ` & `phi` respectively.When they are superimposed internsity of the resultant wave becomes `4I_(0)`. Find `phi`

Options

A. 0
B. `(pi)/( 6)`
C. `( pi)/( 2)`
D. `( pi)/( 3)`

Explanation

To solve the problem, we need to analyze the superposition of three harmonic waves with given phase angles and determine the phase angle `phi` such that the intensity of the resultant wave is `4I0`.

### Step-by-Step Solution:

1. **Understanding the Relationship Between Intensity and Amplitude**:
The intensity `I` of a wave is proportional to the square of its amplitude `A`. Therefore, if the intensity of each wave is `I0`, we can express the amplitude of each wave as:
\[
A_0 = \sqrt{I_0}
...