The velocity of light in diamond, glass and water decreases in the following order:
water > glass > diamond
diamond > glass > water
diamond > water > glass
water > diamond > glass
λa and λm are the wavelengths of a beam of light in air and in a medium respectively. If θ is the polarising angle, the correct relation between λa , λm and θ is
λa = λm tan2 θ
λm = λa tan2 θ
λa = λm cot θ
λm = λa cot θ
Two points separated by a distance of 0.1 mm can just be inspected in a microscope when light of wavelength 6000 Å is used. If the light of wavelength 4800 Å is used, this limit of resolution will become
0.80 mm
0.12 mm
0.10 mm
0.08 mm
The resolution limit of the eye is 1. At a distance of x km from the eye, two persons stand with a lateral separation of 3 metres. For the two persons to be just resolved by the naked eye, x should be
10 km
15 km
20 km
30 km
Diamond has maximum refractive index, hence, velocity of light in diamond is the least. The refractive index of water is the least, hence, in water the velocity of light is maximum.
λ/θ
λ θ
The Young's double slit experiment is performed with blue and with green light of wavelengths 4360 Å and 5460 Å respectively. If x is the distance of the 4th maxima from the central one, then
x(blue) = x(green)
x(blue) > x(green)
x(blue) < x(green)
x(blue) / x(green) = 5460/4360
In Young's experiment, the ratio of maximum and minimum intensities in the fringe system is 9:1. The ratio of amplitudes of coherent sources is
9 :1
3 :1
2 :1
1 :1
Light appears to travel in a straight line because
wavelength of light is very small
frequency of light is very small
light consists of very small particles
velocity is different for different colours
A slit of width a is illuminated by white light. The first minimum for red light will fall at 30o, when a is
3250 Å
6.5 × 10-4 mm
1.3 micron
2.6 x 10-4 mm
In Young's double slit experiment using red and blue lights of wavelengths 600 nm and 480 nm respectively, the value of n for which the nth red fringe coincides with (n + 1)th blue fringe is
