10 Question-answer on photoelectric effect
1. Photo electric shows
(a) Wave like behavior of light
(b) Particle like behavior of light
(c) Both particle and wave like behavior of light
(d) Neither wave like nor particle like behavior of light
Ans: ( b)
2. The best metal to be used for photoemission is
(a) Potassium
(b) Sodium
(c) Cesium
(d) Lithium.
Ans: (c)
3. Light of a particular frequency v is incident on a metal surface. When the intensity of incident radiation is increased, the photo-electric current
(a) Decreases
(b) Increases
(c) Remains unchanged
(d) Sometimes increases and sometime decreases.
Ans: (b)
4. The maximum energy of electrons released in a photocell is independent of
(a) The frequency of the incident light
(b) The intensity of the incident light
(c) The nature of the cathode
(d) All are true.
Ans: ( b)
5. X-rays are used to irradiate sodium and copper surfaces in two separate experiments and stopping potential determined. This stopping potential is
(a) Equal to both cases
(b) Greater for sodium
(c) Greater for copper
(d) Infinite in both cases
Ans: ( b)
6. Sodium surface is illuminated by ultraviolet and visible radiation successively and the stopping potential determined. This stopping potential is:
(a) Equal in both cases
(b) More with ultraviolet light
(c) More with visible light
(d) Varies randomly.
Ans: ( b)
7. In the photoelectric effect, electrons are emitted
(a) At a rate that proportional to the amplitude of the incident radiation
(b) With a maximum velocity proportional to the frequency of the incident radiation
(c) At a rate that is independent of the emitter
(d) Only if the frequency of the incident radiations is above a certain threshold value.
Ans: (d)
8. A metal surface ejects electrons when hit by green light but none when hit by yellow light. The electrons will be ejected when the surface is hit by:
(a) Blue light
(b) Heat rays
(c) Infra-red light
(d) Red light
Ans: (a)
9. Photoelectric effect supports
(a) Huygen’s wave theory of the light
(b) Maxwell’s electromagnetic theory of light
(c) Planck’s quantum theory of light
(d) Newton’s corpuscular theory of the light.
Ans: (c)
10. In photoelectric effect, the photocurrent
(a) Depends both on intensity and frequency of the incident light
(b) Does not depend on the frequency of photon but depends only on intensity of incident light
(c) Decreases with increase frequency of incident photon
(d) Increases with increase of frequency of incident photon.
Ans: (b)