Monochromatic radiation emitted when electron on hydrogen atom jumps from first excited to the ground state irradiates a photosensitive material. The stopping potential is measured to be 3.57 V.The threshold frequency of the material is:
(1)
(2)
(3)
(4)
An \(\alpha -\) particle moves in a circular path of radius 0.83 cm in the presence of a magnetic field of \(0.25 \mathrm{~Wb} / \mathrm{m}^2\). The de-Broglie wavelength associated with the particle will be:
1. | \(1~\mathring {\text{A}}\) | 2. | \(0.1~\mathring {\text{A}}\) |
3. | \(10~\mathring {\text{A}}\) | 4. | \(0.01~\mathring {\text{A}}\) |
If the momentum of an electron is changed by p, then the de-Broglie wavelength associated with it changes by 0.5%. What is the initial momentum of the electron?
1. 200p
2. 400p
3.
4. 100p
A radioactive nucleus of mass M emits a photon
of frequency and the nucleus recoils. The recoil
energy will be:
(1)
(2) zero
(3) h
(4)
Photoelectric emission occurs only when the incident light has more than a certain minimum
1. wavelength
2. intensity
3. frequency
4. power
The threshold frequency for a photo-sensitive metal is If the light of frequency is incident on this metal, the cut-off voltage for the photo-electric emission is nearly:
1. 2 V 2. 3 V
3. 5 V 4. 1 V
The potential difference that must be applied to stop the fastest photoelectrons emitted by a nickel surface having a work function of 5.01 eV when ultraviolet light of 200 nm falls on it is:
1. | 2.4 V | 2. | - 1.2 V |
3. | - 2.4 V | 4. | 1.2 V |
When monochromatic radiation of intensity I falls on a metal surface, the number of photoelectrons and their maximum kinetic energy are N and T respectively. If the intensity of radiation is 2I what is the number of emitted electrons and their maximum kinetic energy?
1. | N and 2T | 2. | 2N and T |
3. | 2N and 2T | 4. | N and T |
The figure shows a plot of photo current versus anode potential for a photo sensitive surface for three difference radiations. Which one of the following is a correct statement?
(1) Curves a and b represent incident radiations of different frequencies and different intensities
(2) Curves a and b represent incident radiations of same frequency but of different intensities
(3) Curves b and c represent incident radiations of different frequencies and different intensities
(4) Curves b and c represent incident radiations of same frequency having same intensity
The wavelength \(\lambda_{e}\) of an electron and \(\lambda_{p}\) of a photon of the same energy E are related as:
1.
2.
3.
4.