For light diverging from a point source:

(a)	the wavefront is spherical.
(b)	the intensity decreases in proportion to the distance squared.
(c)	the wavefront is parabolic.
(d)	the intensity at the wavefront does not depend on the distance.

Choose the correct option:
 

1.	(a), (b)
2.	(a), (c)
3.	(b), (c)
4.	(c), (d)

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

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. \(20~\text{mm}\)

Light is:

Which of the following properties show that light is a transverse wave?
1. reflection
2. interference
3. diffraction
4. polarization

Which of the following sources gives the best monochromatic light?
1. a candle
2. a bulb
3. a mercury tube
4. a laser

The wavefronts of light coming from a distant source of unknown shape are nearly:
1. plane
2. elliptical
3. cylindrical
4. spherical

Two sources are called coherent if they produce waves:

Two coherent sources of different intensities send waves which interfere. The ratio of maximum intensity to the minimum intensity is \(25.\) The intensities of the sources are in the ratio:
1. \(25:1\)
2. \(5:1\)
3. \(9:4\)
4. \(625:1\)