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 amplitudes of electric and magnetic fields in an electromagnetic wave are related to each other as
E0 = B0
E0 = cB0
E0 = B0 /c
E0 = c/B
Which of the following rays are not electromagnetic waves?
β-rays
Heat rays
X-rays
y-rays
The frequency of y-rays, X-rays and ultraviolet rays are a, b and c respectively. Then
a > b > c
a < b < c
a = b = c
a > c > b
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
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 frequency of electromagnetic wave, which is best suited to observe a particle of radius 3 × 10-4 cm, is of the order of
1015
1014
1013
1012
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)
Which one of the following electromagnetic radiations have the smallest wavelength?
Ultraviolet waves
Microwaves
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