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
40.5m
42.3m
36.6m
50.9m
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 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
Which of the following is the longest wave?
x-rays
y-rays
Microwaves
Radiowaves
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)?
4,00,000
4,000
40,000
40,000,00
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
The velocity of electromagnetic radiation in a medium of permittivity ε0 and permeability μ0 is given by
The charging current for a capacitor at any instant is 0.25 A.The displacement current across the capacitor plates at that instant is
0.5 A
0.25 A
1 A
2.5 A
What is the cause of "Green house effect"?
Infra red rays
Ultraviolet rays
X-rays
Which one of the following electromagnetic radiations have the smallest wavelength?
Y-rays
