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

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

Soap bubble appears coloured due to the phenomenon of:
1. Interference
2. Diffraction
3. Dispersion
4. Reflection

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

If an interference pattern has maximum and minimum intensities in a 36 : 1 ratio, then what will be the ratio of their amplitudes?

1. 5 : 7

2. 7 : 4

3. 4 : 7

4. 7 : 5

In Young's experiment, light of wavelength 4000 Å is used to produce bright fringes of width 0.6 mm, at a distance of 2 meters. If the whole apparatus is dipped in a liquid of refractive index 1.5, then fringe width will be:

1. 0.2 mm

2. 0.3 mm

3. 0.4 mm

4. 1.2 mm

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 slits in Young's double-slit experiment have equal widths and the source is placed symmetrically relative to the slits. The intensity at the central fringe is I₀. If one of the slits is closed, the intensity at this point will be:

1. I₀

2. I₀ / 4

3. I₀ / 2

4. 4I₀

In Young's double slit experiment, the angular width of fringe is 0.20^o for sodium light of wavelength 5890 Å.  The angular width of fringe, if the complete system is dipped in water, will be:

1. 0.11^o

2. 0.15^o

3. 0.22^o

4. 0.30^o

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