The velocity of electromagnetic wave is along the direction of
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 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
In a plane electromagnetic wave, the electric field oscillates with a frequency of 2 × 1010 s-1 and an amplitude of 40 Vm-1. The wavelength of the wave is
3 × 10-3 m
2.5 × 10-2 m
1.5 × 10-2 m
4.5 × 10-3 m
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)
Electromagnetic waves are
transverse waves
longitudinal waves
produced by charges moving with constant velocity
none of the above
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
Which of the following is the longest wave?
X-rays
y-rays
Microwaves
Radiowaves
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
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
