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

1.	An increase in fringe intensity
2.	A decrease in fringe intensity
3.	Halving of the fringe spacing
4.	Doubling of the fringe spacing

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 \(1~\text{mm}.\) The distance between the screen and slits is \(1~\text m.\) The distance between third dark and fifth bright fringe will be:
1. \(3.2~\text{mm}\) 
2. \(1.63~\text{mm}\) 
3. \(0.585~\text{mm}\) 
4. \(2.31~\text{mm}\) 

Two superposing waves are represented by the following equations: \(y_1=5 \sin 2 \pi(10{t}-0.1 {x}), {y}_2=10 \sin 2 \pi(10{t}-0.1 {x}).\) 
The ratio of intensities \(\dfrac{I_{max}}{I_{min}}\) 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:

Two coherent sources are \(0.3~\text{mm}\) apart. They are \(1~\text{m}\) away from the screen. The second dark fringe is at a distance of \(0.3~\text{cm}\)  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. \(0.12~\text{cm}\)