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)
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
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 is the longest wave?
X-rays
y-rays
Microwaves
Radiowaves
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
The velocity of electromagnetic radiation in a medium of permittivity ε0 and permeability μ0 is given by
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
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
In a certain region of space electric file and magnetic field are perpendicular to each other and an electron enters in region perpendicular to the direction of and both and moves undeflected, then velocity of electron is
Which of the following rays are not electromagnetic waves?
β-rays
Heat rays
