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
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
Electromagnetic waves are
transverse waves
longitudinal waves
produced by charges moving with constant velocity
none of the above
What is the cause of "Green house effect"?
Infrared rays
Ultraviolet rays
X-rays
Radio-waves
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
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
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
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
Which of the following phenomenon is not common to sound and light waves?
interference
diffraction
coherence
polarisation
