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 $\frac{a}{\lambda} \leq 1$.