Question

In case of diffraction, if \( a \) is a slit width and \( \lambda \) is the wavelength of the incident light, then the required condition for diffraction to take place is:

• A. \( \frac{a}{\lambda} = 1000 \)
• B. \( \frac{a}{\lambda} \leq 1 \)
• C. \( a \ll \lambda \)
• D. \( a \gg \lambda \)

Hint:

Diffraction is significant when the slit width is comparable to or smaller than the wavelength of light.

Answer 1

The Correct Option is B

Step 1: Understanding Diffraction Condition For diffraction to occur, the slit width \( a \) must be of the same order of magnitude as the wavelength \( \lambda \), i.e.: \[ \frac{a}{\lambda} \leq 1 \] Step 2: Explanation - If \( a \gg \lambda \), no noticeable diffraction occurs.
- If \( a \ll \lambda \), diffraction effects are maximized.
- The practical condition is \( \frac{a}{\lambda} \leq 1 \).