Consider sunlight incident on a pinhole of width `10^(3)Å`. The image of the pinhole seen on a screen shall be

Options

A. Be a fine sharp slit white in colour at the centre
B. A bright slit white at the centre diffusing to zero intensities at the edges
C. A bright slit white at the centre diffusing to regions of different colours
D. Only be a diffused slit white in colour

Answer

A

Explanation

Given, width of the slit = `10^(4)Å = 10^(4) xx 10^(-10) m= 10^(-6) m= 1mum`
Wavelength of (visible) sunlight varies from 4000Å to 8000 Å
As the width of slit is comparable to that of wavelength, hence diffraction occurs with maxima at centre. So, at the centre all colours appear i.e., mixing of colours form white patch at the centre.