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 \(I_0\). If one of the slits is closed, the intensity at this point will be:
1. \(I_0\)
2. \(\frac{I_0}{4}\)
3. \(\frac{I_0}{2}\)
4. \(4I_0\)

In Young's double slit experiment, 62 fringes are seen in visible region for sodium light of wavelength 5893 Å. If violet light of wavelength 4358 Å is used in place of sodium light, then number of fringes seen will be 

(1) 54

(2) 64

(3) 74

(4) 84

In Young's double slit experiment, the distance between the two slits is 0.1 mm and the wavelength of light used is 4×10^–7 m. If the width of the fringe on the screen is 4 mm, the distance between screen and slit is 

(1) 0.1 mm

(2) 1 cm

(3) 0.1 cm

(4) 1 m

In Young's double slit experiment using sodium light (λ = 5898 Å), 92 fringes are seen. If given colour (λ = 5461 Å) is used, how many fringes will be seen 

(1) 62

(2) 67

(3) 85

(4) 99

A slit of width a is illuminated by white light. For red light (λ = 6500 Å), the first minima is obtained at θ = 30°. Then the value of a will be 

(1) 3250 Å

(2) 6.5 × 10^–4 mm

(3) 1.24 microns

(4) 2.6 × 10^–4 cm

A parallel monochromatic beam of light is incident normally on a narrow slit. A diffraction pattern is formed on a screen placed perpendicular to the direction of the incident beam. At the first minimum of the diffraction pattern, the phase difference between the rays coming from the edges of the slit is:
1. \(0\)
2. \(\dfrac \pi 2 \)
3. \(\pi\)
4. \(2\pi\)

The angle of polarisation for any medium is \(60^\circ,\) what will be the critical angle for this?

A beam of light AO is incident on a glass slab (μ = 1.54) in a direction as shown in figure. The reflected ray OB is passed through a Nicol prism on viewing through a Nicole prism, we find on rotating the prism that, 

1. the intensity is reduced down to zero and remains zero.
2. the intensity reduces down some what and rises again.
3. there is no change in intensity.
4. the intensity gradually reduces to zero and then again increases.

In the propagation of electromagnetic waves, the angle between the direction of propagation and plane of polarisation is:

(1) 0^o

(2) 45^o

(3) 90^o

(4) 180^o