Wave Optics

The width of one of the two slits in a Young's double slit experiment is 4 times that of the other slit. The ratio of the maximum to the minimum intensity in the interference pattern is:

1. 1 : 1
2. 4 : 1
3. 16 : 1
4. 9 : 1

A monochromatic light of wavelength 6000 is incident on the single slit of width 0.01 mm. If the diffraction pattern is formed at the focus of the convex lens of focal length 20 cm, the linear width of the central maximum is :

1. 12 mm
2. 24 mm
3. 60 mm
4. 120 mm

A microwave of wavelength 2.0 cm falls normally on a slit of width 4.0 cm. The angular spread of the central maxima of the diffraction pattern obtained on a screen 1.5 m away from the slit, will be :

1. 60
2. 45
3. 15
4. 30

When unpolarized light is incident at an angle of 60 on a transparent medium from air, the reflected ray is completely polarized. The angle of refraction in the medium is:

1. 60
2. 90
3. 30
4. 45

The diffraction pattern of a light of wavelength 400 nm diffracting from a slit of width 0.2 mm is focused on the focal plane of a convex lens of focal length 100 cm. The width of the 1st secondary maxima will be :

1. 2 mm
2. 0.2 mm
3. 0.02 mm
4. 2 cm

A beam of unpolarised light of intensity I0 is passed through a polaroid A and then through another polaroid B which is oriented so that its principal plane makes an angle of 45 relative to that of A. The intensity of emergent light is:

1. I0/2
2. I0/8
3. I0/4
4. I0

In Young's double slit experiment, light from two identical sources are superimposing on a screen. The path difference between the two lights reaching at a point on the screen is 7 /4. The ratio of intensity of fringe at this point with respect to the maximum intensity of the fringe is :

1. 12
2. 34
3. 13
4. 14

When a polaroid sheet is rotated between two crossed polaroids then the transmitted light intensity will be maximum for a rotation of :

1. 90
2. 30
3. 45
4. 60