Easy Questions

## Dual Nature Of Radiation And Matter

- It is always better to start confident. Let's practice easy questions to serve the purpose
1
What happens to the stopping potential if the distance between the source and the emitting material increases.
A point source of light is used in a photoelectric effect experiment. If the source is removed farther from the emitting metal, the stopping potential
A
Will increase
B
Will decrease
C
Will remain constant
D
Will either increase or decrease
2
What does the slope of a straight line graph between stopping potential and frequency of incident light signifies? Let's discuss.
In photoelectric effect, the slope of the straight line graph between stopping potential and frequency of the incident light gives the ratio of Planck's constant to
A
Charge of electron
B
Work function
C
Photoelectric current
D
K.E. of electron
3
Effect of a glass plate between a lamp and photoelectric cell.
A quartz lamp with iodine vapour releases ultraviolet light which falls on a photoelectric cell. If a thick glass plate is now introduced between the lamp and photoelectric cell then:
A
the photoelectric current increases
B
the maximum kinetic energy of photoelectrons decreases
C
the photoelectric current decreases
D
the maximum kinetic energy of photoelectrons increases
4
Photoelectric effect and quantum nature of light.
Photoelectric effect supports quantum nature of light because
a) There is a minimum frequency of light below which no photoelectrons are emitted.
b) The maximum kinetic energy of photo electrons depends only on the frequency.
c) Even when the metal surface is faintly illuminated, the photoelectrons leave the surface immediately.
A
a, b
B
b, c
C
a, c
D
a, b, c
5
Dependence of photoelectric current and intensity of light.
Consider the two following statements A and B and identify the correct choice given in the answers:
A) In photovoltaic cells, the photoelectric current produced is not proportional to the intensity of incident light.
B) In gas filled photoemissive cells, the velocity of photoelectrons depends on the wavelength of the incident radiation.
A
Both A and B are true
B
Both A and B are false
C
A is true but B is false
D
A is false but B is true
6
Dependence of Kinetic energy on the photoelectric wavelength
Light of wavelength strikes a photoelectric surface and electrons are ejected with kinetic energy K. If K is to be increased to exactly twice its original value, the wavelength must be changed is such that:
A
B
C
D
7
Concept of wave nature of matter
If the shortest wavelength of the continuous X-ray spectrum coming out of a Coolidge tube is , then the de Broglie wavelength of the electron reaching the target metal in the Coolidge tube is approximately
in  MKS, mass  of  electron
A
B
C
D
8
Calculation of De-Broglie wavelength
If we assume that penetrating power of any radiation/particle is inversely proportional to the De-broglie wavelength of the particle, then
A
A proton and an particle after getting accelerated through same potential difference will have equal penetrating power.
B
Penetrating power of particle will be greater than that of proton which have been accelerated by same potential difference.
C
Proton's penetrating power will be less than penetrating power of an electron which has been accelerated by the same potential difference.
D
Penetrating powers can not be compared as all these are particles having no wavelength or wave nature.
9
Concept of energy of photons in a photoelectric emission
A photon of energy collides inelastically with a Hydrogen atom in ground state. After a certain time interval of few micro seconds another photon of energy collides inelastically with the same hydrogen atom, then the observation made by a suitable detector is
A
1 photon with energy and an electron with energy
B
2 photon with energy
C
2 photon with energy
D
One photon with energy and 1 electron with energy