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
Which of the following rays are not electromagnetic waves?
β-rays
Heat rays
X-rays
y-rays
λa and λm are the wavelengths of a beam of light in air and in a medium respectively. If θ is the polarising angle, the correct relation between λa , λm and θ is
λa = λm tan2 θ
λm = λa tan2 θ
λm = λa cot θ
Which of the following has minimum wavelength?
Ultraviolet rays
Cosmic rays
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
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
The velocity of electromagnetic wave is along the direction of
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
A signal emitted by an antenna from a certain point can be received at another point of the surface in the form of
both (a) and (b)
