Question

In diffraction experiment, from a single slit, the angular width of central maximum does NOT depend upon

• A. ratio of wavelength and slit width
• B. distance of the slit from the screen
• C. wavelength of light used
• D. width of the slit

Hint:

Don't confuse "angular width" with "linear width." Linear width increases as the screen is moved further away, but angular width—the angle subtended at the slit—remains constant.

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
We need to identify which parameter does not affect the angular width of the central maximum in a single-slit diffraction pattern.

Step 2: Key Formula or Approach:
The angular width of the central maximum ($\theta$) is defined by the formula $\theta = \frac{2\lambda}{a}$, where $\lambda$ is the wavelength and $a$ is the slit width.

Step 3: Detailed Explanation:
1. The formula $\theta = \frac{2\lambda}{a}$ shows that angular width depends directly on the wavelength ($\lambda$) and inversely on the slit width ($a$).
2. The ratio $\frac{\lambda}{a}$ also appears in the dependence.
3. The formula for angular width does not include the distance of the slit from the screen ($D$). Note: Linear width ($W = \theta \times D$) would depend on the distance, but the *angular* width is independent of it.

Step 4: Final Answer:
The angular width does not depend on the distance of the slit from the screen, which corresponds to option (B).