Physics - Wave Optics Question with Solution | TestHub

Given:
Slit width, $a=0.5\text{ mm}=0.5\times 10^{-3}\text{ m}$
Distance of screen, $D=2\text{ m}$
Wavelength of light, $\lambda =5500\text{ A˚}=5.5\times 10^{-7}\text{ m}$

The distance between the first minimum on either side of the central maximum is the linear width of the central maximum, which is given by:
$W=\frac{2\lambda D}{a}$

Substituting the given values:
$W=\frac{2\times 5.5\times 10^{-7}\times 2}{0.5\times 10^{-3}}$

$W=\frac{22\times 10^{-7}}{0.5\times 10^{-3}}$

$W=44\times 10^{-4}\text{ m}$

$W=4.4\times 10^{-3}\text{ m}=4.4\text{ mm}$

Answer: 4.4 mm