By Huygen's wave theory of light, we cannot explain the phenomenon of:

1.	Interference
2.	Diffraction
3.	Photoelectric effect
4.	Polarisation

Which of the following statements indicates that light waves are transverse? 

In two separate set-ups of the Young's double slit experiment, fringes of equal width are observed when lights of wavelengths in the ratio 1 : 2 are used. If the ratio of the slit separation in the two cases is 2 : 1, the ratio of the distances between the plane of the slits and the screen in the two set-ups is: 

1. 4 : 1

2. 1 : 1

3. 1 : 4

4. 2 : 1

The direction of the first secondary maximum in the Fraunhofer diffraction pattern at a single slit is given by:
(a is the width of the slit) 

1. $a\sin \theta =\frac{\lambda }{2}$

2. $a\cos \theta =\frac{3\lambda }{2}$

3. $a\sin \theta =\lambda$

4. $a\sin \theta =\frac{3\lambda }{2}$

A parallel beam of monochromatic light of wavelength 5000 Å is incident normally on a single narrow slit of width 0.001 mm. The light is focused by a convex lens on a screen placed on the focal plane. The first minimum will be formed for the angle of diffraction equal to:

1. 0^o

2. 15^o

3. 30^o

4. 60^o

A diffraction pattern is observed using a beam of red light. What will happen if the red light is replaced by the blue light?

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

In Young's double-slit experiment the light emitted from the source has $\lambda$ = 6.5 × 10^–7 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

Two superposing waves are represented by the following equations: 
\({\mathrm{y}_1=5 \sin 2 \pi(10 \mathrm{t}-0.1 \mathrm{x}), \mathrm{y}_2=10 \sin 2 \pi(10 \mathrm{t}-0.1 \mathrm{x}).}\)
Ratio of intensities $\frac{{\mathrm{I}}_{\max }}{{\mathrm{I}}_{\min }}$ 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° 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