A linearly polarized monochromatic light of intensity \(10\) lumen is incident on a polarizer. The angle between the direction of polarization of the light and that of the polarizer such that the intensity of output light is \(2.5\) lumen is:
1. \(60^\circ\)
2. \(75^\circ\)
3. \(30^\circ\)
4. \(45^\circ\)

A monochromatic light of frequency \(500~\text{THz}\) is incident on the slits of Young's double slit experiment. If the distance between the slits is \(0.2~\text{mm}\) and the screen is placed at a distance \(1~\text{m}\) from the slits, the width of \(10\) fringes will be:

Two slits are made one millimetre apart and the screen is placed one metre away. What should the width of each slit be to obtain \(10\) maxima of the double-slit pattern within the central maximum of the single-slit pattern?
1. \(2~\text{mm}\)
2. \(0.2~\text{mm}\)
3. \(0.02~\text{mm}\)
4. \(20~\text{mm}\)

Consider the following statements and then mark the incorrect statement/s.

1. Only b and c
2. Only a
3. Only a, b and c
4. All of the above

Unpolarised light is incident on a plane glass surface. What should be the angle of incidence so that the reflected and refracted rays are perpendicular to each other?

$1. {45}^0$
$2. {67}^0$
$3. {57}^0$
$4. {37}^0$

The expression for intensity (as shown in the figure) of transmitted light when a polaroid sheet is rotated between two crossed polaroids is:
[Given: \(I_0\) is the intensity of transmitted light from polariser \(\mathrm{A}\)]