Ncert Exercises & Solutions

Consider sunlight incident on a pinhole of width $10^{3}$ $\overset{\circ}{A}$ . The image of the pinhole seen on a screen shall be:

(a) a sharp white ring
(b) different from a geometrical image
(c) a diffused central spot, white in colour
(d) diffused coloured region around a sharp central white spot

1. (a, c)

2. (a, d)

3. (b, d)

4. (b, c)

(b, d) Hint: The diffraction occurs when the size of the obstacle in the path of light is comparable to the wavelength of the light.

Step 1: Find the shape of the image.
Given, width of pinhole = $10^{3}$ $\overset{\circ}{A}$ = 1000 $\overset{\circ}{A}$
We know that wavelength of sunlight ranges from 4000 A to 8000 $\overset{\circ}{A}$ .

Clearly, wavelength $λ$ < width of the slit.
Hence, light is diffracted from the hole. Due to diffraction from the slit, the image formed
on the screen will be different from the geometrical image.

NEET Information

courses

Company

Botany Questions

Chemistry Questions

Physics Questions

Zoology Questions