Question

A laser beam is incident on two slits with a separation of 0.230 mm, and a screen is placed 4.75 m from the slits. If the bright interference fringes on the screen are separated by 1.56 cm, what is the wavelength of the laser light

Answer 1

Answer:

$7.55\times 10^{-7} m$

Explanation:

We are given that

d=0.23 mm=$0.23\times 10^{-3} m$

$1mm=10^{-3} m$

Screen is placed  from the slits at distance ,L=4.75 m

The bright interference fringes on the screen are separated  by 1.56 cm.

$\Delta y=1.56 cm=1.56\times 10^{-2} m$

1 m=100 cm

We have to find the wavelength of laser light.

We know that

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

Substitute the values

$1.56\times 10^{-2}=\frac{\lambda\times 4.75}{0.23\times 10^{-3}}$

$\lambda=\frac{1.56\times 10^{-2}\times 0.23\times 10^{-3}}{4.75}$

$\lambda=7.55\times 10^{-7} m$