Question

The width of the diffraction band varies

• A. inversely as the wavelength
• B. directly as the width of the slit
• C. directly as the distance between the slit and the screen
• D. inversely as the size of the source from which the slit is illuminated

Answer 1

Answer: (C)

directly as the distance between the slit and the screen

Answer 2

Width of the diffraction band is given by
$\beta=\frac{\lambda D}{d}$
where $D=$ distance between slit and the screen
$\lambda=$ wavelength of light used and
$d=$ width of slit.
Hence, width of the diffraction band varies directly as the distance between the slit and the screen.