The ground state energy H-atom is 13.6 eV. The energy needed to ionize H –atom from its second excited state is
1.51 eV
3.4 eV
13.6 eV
12.1 eV
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 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
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
Which of the following rays are not electromagnetic waves?
β-rays
Heat rays
X-rays
y-rays
The velocity of electromagnetic wave is along the direction of
The frequency of electromagnetic wave, which is best suited to observe a particle of radius 3 × 10-4 cm, is of the order 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
40.5 m
42.3 m
36.6 m
50.9 m
What is the cause of "Green house effect"?
Infrared rays
Ultraviolet rays
Radio-waves
