The velocity of electromagnetic radiation in a medium of permittivity ε0 and permeability μ0 is given by
If a source is transmitting electromagnetic waves of frequency 8.2 × 106 Hz, then wavelength of the electromagnetic waves transmitted from the source will be
40.5 m
42.3 m
36.6 m
50.9 m
The structure of solids is investigated by using
cosmic rays
X-rays
y-rays
infrared radiations
Which one of the following electromagnetic radiations have the smallest wavelength?
Ultraviolet waves
Microwaves
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
The velocity of electromagnetic wave is along the direction of
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
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
What is the cause of "Green house effect"?
Infrared rays
Ultraviolet rays
Radio-waves
A signal emitted by an antenna from a certain point can be received at another point of the surface in the form of
sky wave
ground wave
sea wave
both (a) and (b)
