If the polarizing angle of a piece of glass for green light is 54.74°, then the angle of minimum deviation for an equilateral prism made of same glass is[Given, tan 54.74° =1.414]

45°
54.74°
60°
30°

Solution

Aperture of the human eye is 2 mm. Assuming the mean wave length of light to be 5000 Å, the angular resolution limit of the eye is nearly

2 minute
1 minute
0.5 minute
1.5 minute

Solution

In young’s double-slit experiment, the intensity of light at apoint on the screen where the path difference is λ is I, λ being the wavelength of light used. The intensity at a point where the path difference is ^λ⁄₄ will be

^I⁄₄
^I⁄₂
I
zero

Solution

Fluorescent tubes give more light than a filament bulb of same power because

the tube contains gas at low temperature
ultraviolet light is converted into visible light by fluorescence
light is diffused through the walls of the tube
it produces more heat than bulb

Solution

The fluorescent material present in the tube converts u.v. rays into visible light.

The heavenly body is receding from earth, such that the fractional change in λ is 1, then its velocity is

c
^3c⁄₅
^c⁄₅
^2c⁄₅

Solution

A rocket is receding away from earth with velocity 0.2 c.The rocket emits signal of frequency 4 × 10⁷Hz. The apparent frequency observed by the observer on earth will be

4 × 10⁶ Hz
3.2 × 10⁷ Hz
3 × 10⁶ Hz
5 × 10⁷ Hz

Solution

A beam of unpolarised light passes through a tourmaline crystal A and then through another such crystal B oriented so that the principal plane is parallel to A. The intensity of emergent light is I₀. Now B is rotated by 45º about the ray.The emergent light will have intensity

I₀/2
I₀/√2
I₀√2
2I₀

Solution

Two nicols are oriented with their principal planes making an angle of 60º. Then the percentage of incident unpolarised light which passes through the system is

100
50
12.5
37.5

Solution

A parallel beam of monochromatic unpolarised light is incidenton a transparent dielectric plate of refractive index \(\frac{1}{\sqrt{3}}\). The reflected beam is completely polarised. Then the angle of incidence is

30º
60º
45º
75º

Solution

When angle of incidence i is equal to angle of polarisation i.e, then reflected light is completely plane-polarised whose vibration is perpendicular to plane of incidence

Unpolarised light of intensity 32 W m–2 passes through three polarizers such that the transmission axis of the last polarizer is crossed with that of the first. The intensity of final emerging light is 3 W m–2. The intensity of light transmitted by first polarizer will be

32 W m^–2
16 W m^–2
8 W m^–2
4 W m^–2

Solution

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