The intensity on the screen at a certain point in a double-slit interference patteren is 25.0% of the maximum value. (a) What minimum phase difference (in radians) between the sources produces this result? (b) Express this phase difference as a path difference for 486.1 nm light.

Explanation

To solve the problem step by step, let's break it down into two parts as per the question.

### Part (a): Finding the Minimum Phase Difference

1. **Understanding the relationship between intensity and phase difference**:
The intensity \( I \) at a point in a double-slit interference pattern can be expressed as:
\[
I = I_{\text{max}} \cos^2\left(\frac{\phi}{2}\right)
...