Physics - Wave Optics Question with Solution | TestHub

Given:
Wavelength of light, $\lambda =6000\text{ A˚}=6000\times 10^{-8}\text{ cm}=6\times 10^{-5}\text{ cm}$
Distance of the screen from the slits, $D=40\text{ cm}$
Fringe width, $W=0.012\text{ cm}$

The formula for fringe width is:
$W=\frac{\lambda D}{d}$

Rearranging for the distance between the two slits $d$:
$d=\frac{\lambda D}{W}$

Substituting the given values:
$d=\frac{6\times 10^{-5}\times 40}{0.012}$

$d=\frac{240\times 10^{-5}}{12\times 10^{-3}}$

$d=20\times 10^{-2}\text{ cm}$

$d=0.2\text{ cm}$

Answer: 0.2 cm