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_o is the intensity of transmitted light from polariser A]

$1. \mathrm{I}=\frac{{\mathrm{I}}_0}{2}{\sin }^{2}2\mathrm{\theta }$
$2. \mathrm{I}=\frac{{\mathrm{I}}_0}{4}{\sin }^{2}2\mathrm{\theta }$
$3. \mathrm{I}=\frac{{\mathrm{I}}_0}{2}{\cos }^{2}2\mathrm{\theta }$
$4. \mathrm{I}=\frac{{\mathrm{I}}_0}{4}{\cos }^{2}2\mathrm{\theta }$

For what distance is ray optics a good approximation when the aperture is \(3\) mm wide and the wavelength is \(500\) nm?
1. \(32\) m
2. \(42\) m
3. \(18\) m
4. \(20\) m

Assume that light of wavelength 6000Å is coming from a star. What is the limit of resolution of a telescope whose objective has a diameter of 100 inches?

$$\begin{gathered} 1. 1.2\times {10}^{-6} \mathrm{radians} \\ 2. 3.3\times {10}^{-7} \mathrm{radians} \\ 3. 1.7\times {10}^{-6} \mathrm{radians} \\ 4. 2.9\times {10}^{-7} \mathrm{radians} \end{gathered}$$

Two slits are made one millimetre apart and the screen is placed one meter away. What is the fringe separation when blue-green light of wavelength \(500\) nm is used? 
1. \(0.5\) mm
2. \(0.3\) mm
3. \(0.05\) mm
4. \(0.03\) mm

Which one of the following is incorrect?

What speed should a galaxy move with respect to us so that the sodium line at 589.0 nm is observed at 589.6 nm?

1. 164 km/s

2. 332 km/s

3. 102 km/s

4. 306 km/s

Two coherent sources of light interfere and produce fringe patterns on a screen. For the central maximum, the phase difference between the two waves will be: 
1. zero 
2. \(\pi\)
3. \(\frac{3\pi}{2}\)
4. \(\frac{\pi}{2}\)$$