Question

Angular width $(\theta )$ of central maximum of a diffraction pattern of a single slit does not depend upon:

• A. distance between slit and source
• B. wavelength of light used
• C. width of the slit
• D. frequency of light used

Answer 1

Answer: (A)

The following ray diagram shows the single slit diffraction pattern.
This is guided by Huygens principle.
The properties of the system are wholly dependent on the ratio
$\frac{\lambda }{W}$ where $\lambda$
is wavelength and W the width of slit.
Angular width $=\frac{\lambda }{W}$
Hence, angular width does not depend upon the distance between slit and source.