Question

Smallest distance on the screen where there is poor intensity

Answer 1

Answer:

Smallest distance =0.25m

After coming thin close to any object we cannot see properly...

Answer 2

We now begin a discussion of wave (physical) optics in which - in contrast to geometric optics - we explicitly consider the wave nature of light. Remember, in geometric optics light traveled in straight lines (light rays). This is a valid approximation so long as we do not consider apertures with dimensions similar to the wavelength of the light or look too closely at the edges of objects.

So what happens when a wave passes through apertures whose size is similar to the wavelength of the wave ? First we'll consider the case of double slit interference, in which a parallel beam of incident monochromatic (containing a specific wavelength) light from the left strikes a screen with two slits, S1 and S2 , as below.

interference fig1