Q10.19 A parallel beam of light of wavelength 500 nm falls on a narrow slit and the resulting diffraction pattern is observed on a screen 1 m away. It is observed that the first minimum is at a distance of 2.5 mm from the centre of the screen. Find the width of the slit.
Given
Distance of screen from the slit,
Distance of first minimum
The wavelength of the light
Now,
As we know,
Hence, the width of the slit is 0.2 mm.