Two polaroids are kept crossed to each other. Now one of them is rotated through an angle of \(45^{\circ}\)
1. \(15\%\)
2. \(25\%\)
3. \(50\%\)
4. \(60\%\)
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:
1. | the intensity is reduced down to zero and remains zero. |
2. | the intensity reduces down somewhat and rises again. |
3. | there is no change in intensity. |
4. | the intensity gradually reduces to zero and then again increases. |
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:
1. | zero | 2. | \(I_0\) |
3. | \(\dfrac{I_0}{2}\) | 4. | \(\dfrac{I_0}{4}\) |
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. \(90\)
1. | \(\dfrac{1}{\sqrt{3}}\) | 2. | \(\dfrac{3}{2}\) |
3. | \(\sqrt{3}\) | 4. | \(\dfrac{\sqrt{3}}{2}\) |
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:
1. | \(\dfrac{I_0}{4}\) | 2. | \(\dfrac{I_0}{8}\) |
3. | \(\dfrac{I_0}{16}\) | 4. | \(\dfrac{I_0}{32}\) |
In Young's double-slit experiment, the ratio of maximum intensity at a point to the intensity at the same point when one slit is closed, is:
1. \(2\)
2. \(3\)
3. \(4\)
4. \(1\)
Two light sources are said to be coherent when their:
1. | amplitudes are equal and have a constant phase difference. |
2. | wavelengths are equal. |
3. | intensities are equal. |
4. | frequencies are equal and have a constant phase difference. |