If the threshold wavelength for a certain metal is 2000Å, then the work function of the metal is
6.2 J
6.2 eV
6.2 MeV
6.2 keV
In photoelectric effect, the work function of a metal is 3.5 eV. The emitted electrons can be stopped by applying a potential of - 1.2 V. Then
the energy of the incident photons is 4.7 eV
the energy of the incident photons is 2.3 eV.
if higher frequency photons be used, the photoelectric current will rise
when the energy of photos is 3.5 eV, the photoelectric current will be maximum
The work function of a surface of a photosensitive material is 6.2 eV. The wavelength of the incident radiation for which the stopping potential is 5 V lies in the
ultraviolet region
visible region
infrared region
X-ray region
A radio transmitter operates at a frequency 880 KHz and a power of 10 kW. The number of photons emitted per second is
1.72 × 1031
1.327 × 1025
1.327 × 1037
1.327 × 1045
Doubly ionised helium atoms and hydrogen ions are accelerated from rest through the same potential drop. The ratio of the final velocities of the helium and the hydrogen ion is
2
The figure shows a plot of photo current versus anode potential for a photo sensitive surface for three different radiations. Which one of the following is a correct statement ?
Curves a and b represent incident radiations of different frequencies and different intensities
Curves a and b represent incident radiations of same frequency but of different intensities
Curves b and c represent incident radiations of different frequencies and different intensities
Curves b and c represent incident radiations of same frequency having same intensity
The momentum of a photon of energy 1 MeV in kg m/s, will be
0.33 × 106
7 × 10-24
10-22
5 × 10-22
A photocell employs photoelectric effect to convert
change in the frequency of light into a change in electric voltage
change in the intensity of illumination into a change in photoelectric current
change in the intensity of illumination into a change in the work function of the photo cathode
change in the frequency of light into a change in the electric current
An electron moves with a velocity 1 ×103 m/s in a magnetic field of induction 0.3 T at an angle 30o. If of electron is 1.76 × 1011 C/kg, the radius of the path is nearly
10-8 m
2 × 10-8 m
10-6 m
10-10 m
According to Einstein's photoelectric equation, the graph between the kinetic energy of photo electrons ejected and the frequency of incident radiation is
