Ozone layer blocks the radiations of wave length
less than 3 × 10-7 m
equal to 3 × 10-7 m
more than 3 × 10-7 m
all of the above
Two sodium lamps are used in an interference experiment. The intensity produced by both lamps individually on the screen is I. The ratio of intensity of maxima to intensity of minima on the screen is
∞:1
What is the cause of "Green house effect"?
Infrared rays
Ultraviolet rays
X-rays
Radio-waves
The velocity of electromagnetic radiation in a medium of permittivity ε0 and permeability μ0 is given by
A TV tower has a height of 100 m. How much population is covered by the TV broadcast if the average population density around the tower is 1000 km-2 (radius of earth = 6370 km)?
4 lakh
40,000
4000
40 lakh
Which of the following phenomenon is not common to sound and light waves?
interference
diffraction
coherence
polarisation
If λv, λx and λm represent the wavelengths of visible light, X-rays and microwaves respectively, then
λm > λx > λv
λv > λm > λx
λm > λv > λx
λv > λx > λm
The frequency of y-rays, X-rays and ultraviolet rays are a, b and c respectively. Then
Electromagnetic waves are
transverse waves
longitudinal waves
produced by charges moving with constant velocity
none of the above
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
