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
None of these
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
The velocity of electromagnetic radiation in a medium of permittivity ε0 and permeability μ0 is given by
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
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
The velocity of electromagnetic wave is along the direction of
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
Radiowaves
Which of the following is the longest wave?
x-rays
y-rays
Microwaves
The frequency of y-rays, X-rays and ultraviolet rays are a, b and c respectively. Then
a>b>c
a
a=b-c
a>c>b
