Two polaroids are kept crossed to each other. Now one of them is rotated through an angle of $\mathrm{}$\(45^{\circ}\). The percentage of incident light now transmitted through the system is:
1. \(15\%\)
2. \(25\%\)
3. \(50\%\)
4. \(60\%\)

The distance of the moon from the earth is $3.8\times {10}^5<mspace\; width="1em"></mspace>km$. The eye is most sensitive to light of wavelength 5500 Å. The minimum separation between two points on the moon that can be resolved by a 500 cm telescope will be:

1. 51 m                         

2. 60 m

3. 70 m                         

4. All the above

The ratio of resolving powers of an optical microscope for two wavelengths ${\lambda }_1=4000<mspace\; width="1em"></mspace>\stackrel{o}{A<mspace\; width="1em"></mspace>}<mspace\; width="1em"></mspace>and<mspace\; width="1em"></mspace>{\lambda }_2=6000<mspace\; width="1em"></mspace>\stackrel{o}{A}$ is:

1. 8:27

2. 9:4

3. 3:2

4. 16:81

A beam of light \(AO\) is incident on a glass slab \((\mu= 1.54)\) in a direction as shown in the figure. The reflected ray \(OB\) is passed through a Nicol prism. On viewing through a Nicole prism, we find on rotating the prism that:

Unpolarized light of intensity \(32\) Wm^–2 passes through three polarizers such that the transmission axes of the first and second polarizer make an angle of \(30^{\circ}\) with each other and the transmission axis of the last polarizer is crossed with that of the first. The intensity of the final emerging light will be:
1. \(32\) Wm^–2
2. \(3\) Wm^–2
3. \(8\) Wm^–2
4. \(4\) Wm^–2

When an unpolarized light of intensity \(I_0\) is incident on a polarizing sheet, the intensity of the light which does not get transmitted is:

In Young's double-slit experiment using the light of wavelength \(\lambda\), \(60\) fringes are seen on a screen. If the wavelength of light is decreased by \(50\%\), then the number of fringes on the same screen will be:
1. \(30\)
2. \(60\)
3. \(120\)
4. \(90\)

Five identical polaroids are placed coaxially with \(45^{\circ}\) angular separation between pass axes of adjacent polaroids as shown in the figure. (\(I_0\): Intensity of unpolarized light)
          
The intensity of light, \(I\), emerging out of the \(5\)^th polaroid is: