Question

A laser beam is incident on two slits with a separation of 0.180 mm, and a screen is placed 5.05 m from the slits. If the bright interference fringes on the screen are separated by 1.62 cm, what is the wavelength of the laser light

Answer 1

Answer:

The answer is "530 nm".

Explanation:

$d=0.180 \ nm=0.180 \times 10^{-3} \ m\\\\L= 5.05\ m\\\\\Delta y= 1.62\ cm= 1.62 \times 10^{-2} \ m$

Using formula:

$\Delta y=\frac{\lambda L}{d}\\\\\lambda =\frac{d\Delta y}{L}$

  $=\frac{0.180 \times 10^{-3} \times 1.62 \times 10^{-2} }{5.05}\\\\=5.30 \times 10^{-9} \times \frac{1 \ nm}{10^{-9} \ m}\\\\=530 \ nm$