In Young's double-slit experiment the light emitted from the source has \(\lambda = 6.5\times 10^{-7}~\text{m}\) and the distance between the two slits is \(1\) mm. The distance between the screen and slits is \(1\) metre. Distance between third dark and fifth bright fringe will be:
1. \(3.2\) mm 
2. \(1.63\) mm
3. \(0.585\) mm
4. \(2.31\) mm

In Young's double-slit experiment, the slit separation is doubled. This results in:

Two superposing waves are represented by the following equations: 
\(y_1=5 \sin 2 \pi(10{t}-0.1 {x}), {y}_2=10 \sin 2 \pi(10{t}-0.1 {x}).\)
Ratio of intensities \(\frac{I_{max}}{I_{min}}\) will be:
1. \(1\)
2. \(9\)
3. \(4\)
4. \(16\)

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

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:

Two light sources are said to be coherent when their:

Light waves of intensities \(I\) and \(9I\) interfere to produce a fringe pattern on a screen. The phase difference between the waves at point \(P\) is \(\frac{3\pi}{2}\) and \(2\pi\) at other point \(Q\). The ratio of intensities at \(P\) and \(Q\) is:
1. \(8:5\)
2. \(5:8\)
3. \(1:4\)
4. \(9:1\)

Two coherent sources are \(0.3\) mm apart. They are \(1\) m away from the screen. The second dark fringe is at a distance of \(0.3\) cm from the center. The distance of the fourth bright fringe from the centre is:
1. \(0.6~\text{cm}\)
2. \(0.8~\text{cm}\)
3. \(1.2~\text{cm}\)
4. \(0.12~\text{cm}\)