Q.1.
Kinetic energy of an electron, which is accelerated in a potential difference of 100V is [ CBSE - PMT 1995]
-
33%
a) 1.6×10-17J
-
33%
b) 1.6×10-19J
-
33%
c)1.6×10-21
-
0%
d)1.6×10-25J
Q.2.
In photo-emissive cell, with exciting wave length λ, the fastest electron speed 'v' . If the exciting wavelength is changed to 3λ / 4 , the speed of the fastest emitted electron will be [ CBSE-PMT 1998]
-
0%
a) (3/4) 1/2 v
-
50%
b) (4/3) 1/2 v
-
50%
c) less than (4/3) 1/2 v
-
0%
d) grater than (3/4) 1/2 v
Explanation
Q.3.
When photoelectric emission is taking place increasing the intensity of light will [ EAMCET 1995, MPPMT 1994]
-
0%
a)have no effect
-
100%
b) increase the number of electrons released
-
0%
c)increases the maximum energy per electron
-
0%
d)causes a time delay in the emission of electrons
Q.4.
A photo cell is illuminated by a small bright source of light is placed two metres away, the electrons emitted by the photocathode ..[ MNR 1986]
-
0%
a) each carries one quarter of its previous energy
-
0%
b) each carries one quarter of its previous momentum
-
100%
c)are half as numerous
-
0%
d)are one quarter as numerous
Q.5.
Given that a photon of light of wavelength 10,000Å has an energy equal to 1.23 eV, when light of wave length 5000Å and intensity I0 falls on photoelectric cell and the saturation current is 0.40×10-6 ampere stopping potential is 1.36 V. Then the work function is .. [ CPMT 1977]
-
0%
a) 0.43 eV
-
50%
b) 1.10eV
-
50%
c)1.36eV
-
0%
d)2.47eV
Q.6.
Photoelectric effect is the phenomenon in which ..[ MNR1992]
-
0%
a) Photons come out of metal when it is heat by a beam of electrons
-
0%
b) Photons come out of the nucleus of an atom under the action of an electric field
-
50%
c) Electrons come out of a metal with a constant velocity which depends up on the frequency and intensity of incident light wave
-
50%
d) Electrons come out of metal with different velocities not greater than a certain value which depends only on the frequency of incident light wave and not on its intensity
Q.7.
What is the stopping potential, when the metal with work function 0.6 eV is illuminated with light of 2eV [ BHU 1998]
-
0%
a)2.6 V
-
0%
b) 3.6 V
-
0%
c)0.8 V
-
100%
d)1.4 V
Q.8.
Photoelectric effect supports
-
0%
a) Newton's corpuscular nature of light
-
0%
b) Huyen's wave theory of light
-
0%
c)Maxwell's electromagnetic theory of light
-
100%
d)Einstein's quantum theory of light
Q.9.
The photoelectrons emitted from a metal surface are such that
-
0%
a) They are all at rest
-
50%
b) They all have the same energy
-
0%
c)Their energy varies from 0 to ∞
-
50%
d)Their energy varies from 0 to a finite maximum value
Q.10.
Work function of tungsten and sodium are 4.4 eV and 2.3eV respectively. If threshold wave length of sodium is 5460Å , then the threshold wavelength of tungsten is [ Raj. PMT 1993]
-
50%
a) 11360Å
-
50%
b) 8000Å
-
0%
c) 6000Å
-
0%
d) 2854Å
Explanation
Q.11.
Light of frequency 1.5 times the threshold frequency is incident on photosensitive material. If the frequency is halved and intensity is doubled, the photo current becomes [ EAMCET 1991]
-
50%
a)Quadrupled
-
0%
b) Doubled
-
0%
c)Halved
-
50%
d)Zero
Q.12.
In Einstein's photo-electric equationEkin=hν - φ Ekin stands for [ MPPMT 1997]
-
0%
a) kinetic energy of all the emitted electrons
-
0%
b) mean kinetic energy of the emitted electrons
-
0%
c)maximum kinetic energy of the emitted electrons
-
100%
d)minimum kinetic energy of the emitted electrons
Q.13.
When photons of energy hν fall on a photo sensitive metallic surface ( work function hνo) electrons emitted from the metallic surface. Then
-
0%
a) All ejected electrons have same kinetic energy equal to hν - hν0
-
0%
b)The maximum kinetic energy is equal to hν - hν0
-
100%
c)The maximum kinetic energy hν
-
0%
d)The kinetic energy of ejected electron is hνo
Q.14.
in photoelectric effect, the photoelectric current ..[ EAMCET 85]
-
0%
a) Does not depend on photo frequency, but only on intensity of incident bean
-
0%
b) depends both intensity and frequency of incident beam
-
50%
c) increase when frequency of incident photos increases
-
50%
d) decrease when frequency of incident photons increases
Q.15.
The maximum energy of the electrons released in photocell is independent of [ EAMCET]
-
0%
a)frequency of incident light
-
0%
b) intensity of incident light
-
100%
c)nature of cathode surface
-
0%
d)none of these
Q.16.
Plank's constant has the dimensions of [ NCERT 1990]
-
0%
a) Force
-
0%
b) Energy
-
50%
c)Linear momentum
-
50%
d)Angular momentum
Q.17.
X-rays are used to irradiate sodium and copper surface in two separate experiments and stopping potential determined. The stopping potential is
-
0%
a) Equal in both the cases
-
0%
b) Greater for sodium
-
50%
c)Greater for copper
-
50%
d)Infinite in both the cases
Q.18.
The variation of photoelectric current given by the photocell with the intensity of light is given by a graph which is
-
0%
a) A parabola
-
0%
b) A straight line with posittive slope passing through origin
-
50%
c) A straight line with positive slope with intercept on current axis
-
50%
d) A straight line with negative slope
Q.19.
An electromagnetic radiation of frequency 3×1015 c/s fall on a photoelectric surface whose work function is 4.0eV. The maximum velocity of photoelectrons emitted by the surface is ( h=6.6×10-34 Js) [ JIMPER 19989]
-
0%
a)1.73×106 m/sec
-
100%
b) 1.73×105 m/sec
-
0%
c)1.73×104 m/sec
-
0%
d)1.73×103 m/sec
Q.20.
The stopping potential as function of frequency of incident radiation is plotted for two different photoelectric surfaces A and B. The graphs show that the work function of A is .. [ PMT 1992]
-
100%
a) Greater than that of B
-
0%
b) smaller than that of B
-
0%
c)same as that of B
-
0%
d)No comparison can be done from the given graphs
Q.21.
If the distance of 100 watt lamp is increased from a photocell, the saturation current 'i' in the photocell varies with distance 'd' as [ NCERT 1990]
-
50%
a) i ∝ d2
-
0%
b) i ∝ d
-
50%
c)i ∝ 1/ d
-
0%
d)i ∝ 1/d2
Q.22.
The work function for photo-electric effect: [ JIMPER 1998]
-
0%
a) is different for different metals
-
0%
b) is same for all metals
-
0%
c) depends upon the frequency of the incident light
-
100%
d) none of the above
Q.23.
When a monochromatic point source of light is at a distance of 0.2m from a photoelectric cell, the cut off voltage and saturation current are respectively 0.6V and 18.0 mA. If the same source is placed 0.6 m away from photocell, the [ IIT 1992]
-
50%
a) The stopping potential will be 0.2V
-
50%
b) The stopping potential will be 0.4V
-
0%
c) The sturation current will be 6.0 mA
-
0%
d) The saturation current will be 0.2 mA
Q.24.
Which of the following statement is wrong
-
0%
a) Wave nature of particles is not exhibited in daily life
-
0%
b) de Broglie waves are probability waves
-
0%
c)Wavelength of de-Broglie waves is proportional to the momentum of particle
-
100%
d)de-Broglie waves are associated with charged as well as uncharged particles
Q.25.
Matter waves associated with moving material particles are
-
0%
a) Electromagnetic waves
-
0%
b) Imaginary waves
-
0%
c)Mechanical waves
-
100%
d)Probability waves
Q.26.
Ultraviolet light of wave length 300 nm and intensity 1.0 watt/m2 fall on the surface of a photosensitive material. If one per cent of the incident photons produce photoelectrons then the number of photoelectrons emitted from an area of 1.0 cm2 of the surface is nearly [ AMU 1995]
-
0%
a) 9.61×1014 per sec
-
0%
b) 4.12 ×1013 per sec
-
100%
c)1.51×1014 per sec
-
0%
d)2.13×1011 per sec
Explanation
Q.27.
When a certain metallic surface is illuminated with monochromatic light of wavelength λ, the stopping potential for photoelectric current is 3VWhen the same surface is illuminated by wavelength 2λ the stopping potential is VThe threshold wavelength for this surface for photoelectric effect is ..[ CPMT 1998]
-
0%
a) 6λ
-
50%
b) 4λ
-
50%
c)λ/4
-
0%
d)8λ
Q.28.
the frequency and intensity of the incident beam of light falling on the surface of photoelectric material is increased by a factor of two. this will [ CPMT 1988}
-
0%
a) Increase the maximum kinetic energy of the photoelectrons as well as photoelectric current by a factor of two
-
50%
b) Increase the maximum kinetic energy of photoelectrons and would increase the photoelectric current by a factor of two
-
0%
c) Increase the maximum kinetic energy of photoelectrons by a factor of two and will have no effect on photo electric current
-
50%
d) Increase the photoelectric current by a factor of two but will have no effect on the kinetic energy of emitted electrons
Q.29.
Given h=6.6×10-14 joules×sec. The momentum of each photon in give radiation is 3.3×10-29 kg×metre (sec)-The frequency of radiation is [ CBSE 1990]
-
0%
a)3×10-2 hz
-
100%
b) 6×1010
-
0%
c)7.5×1012 hz
-
0%
d)1.5×1013 hz
Q.30.
The threshold wavelength for photoelectric emission from a material is 5200Å. Photoelectrons will be emitted when this material is illuminated with monochromatic radiation from a [ MPPMT 1999]
-
0%
a) 50 watt infra-red lamp
-
50%
b) 1 watt infrared lamp
-
50%
c)50 watt ultraviolet lamp
-
0%
d)1 watt ultraviolet lamp