# Topic Photoelectric Effect and Matter Wave, Class 12 Physics MCQ Quiz Test

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MCQ 1:
Two different photons of energies, 1 eV and 2.5 eV, fall on two identical metal plates having work function 0.5 eV, Then the ratio of maximum KE of the electrons emitted from the two surface is-

MCQ 2:
Ultraviolet light of wavelength 280 nm is used in an experiment on photo electric effect with lithium (φ = 2.5 eV) cathode. Stopping potential will be-

MCQ 3:
A monochromatic source of light operating at 200 W emits 4 × 1020 photons per second. Find the wavelength of light.

MCQ 4:
Which metal will be suitable for a photo electric cell using light of wavelength 4000Å. The work functions of sodium and copper are respectively 2.0 eV and 4.0 eV.

MCQ 5:
The work function for the surface of aluminum is 4.2 eV. What will be the wavelength of that incident light for which the stopping potential will be zero.

MCQ 6:
Slope of V0 – ν curve is -

MCQ 7:
A radio station is transmitting waves of wavelength 300 m, If diffracting power of transmitter is 10 kw, then numbers of photons diffracted per second is-

MCQ 8:
Light of wavelength 332 Å incidents on metal surface (work function = 1.07 eV). To stop emission of photo electron, retarding potential required to be-

MCQ 9:
Light of wavelength 5000 Å falls on a sensitive surface. If the surface has received 10–7 Joule of energy, then what is the number of photons falling on the surface ?

MCQ 10:
An electromagnetic radiation of frequency 3 × 1015 cycles per second falls on a photo electric surface whose work function is 4.0 eV. Find out the maximum velocity of the photo electrons emitted by the surface-

MCQ 11:
The wavelength of a photon is 4000 Å. Calculate its energy.

MCQ 12:
When ultraviolet light of energy 6.2 eV incidents on a aluminimum surface, it emits photo electrons. If work function for aluminium surface is 4.2 eV, then kinetic energy of emitted electrons is-

MCQ 13:
Using light of wavelength 6000 Å stopping potential is obtained 2.4 volt for photo electric cell. If light of wavelength 4000 Å is used then stopping potential would be-

MCQ 14:
When light source is placed at 1 m distant from photo electric cell, then value of stopping potential is obtained 4 volt. If it is placed at 4 m distant, then value of stopping potential becomes -

MCQ 15:
When monochromatic light of wavelength &lamda; illuminates a metal surface then stopping potential for photo electric current is 3V0. If wavelength changes to 2λ then stopping potential becomes V0 . Threshold wavelength for photo electric emission is-

MCQ 16:
The graph between the energy of photoelectrons (E) and the wavelength of incident light (λ) is -

MCQ 17:
For a photoelectric cell, the graph showing the variation of cut off voltage (V0) with frequency (ν) of incident light is -

MCQ 18:
The K.E. of the photoelectrons is E when the incident wavelength is &lamda;/2. The K.E. becomes 2E when the incident wavelength is &lamda;/3. The work function of the metal is -

MCQ 19:
One electron & one proton is accelerated by equal potential. Ratio in their de-broglie wavelength is

MCQ 20:
De-broglie wavelength of a electron is 10 Å then velocity will be -

MCQ 21:
One electron & one proton have equal energies then ratio of associated de-broglie wavelength will be -

MCQ 22:
Ratio of wavelength of duetron & proton accelerated by equal potential-

MCQ 23:
Energy of a α-particle, having debroglie wavelength of 0.004 Å.

MCQ 24:
Velocity of a proton is c/20. Associated de-broglie wavelength is -

MCQ 25:
Associated de-broglie wavelength of a electron in nth bohr's orbit is -

MCQ 26:
De-broglie wavelength of a rotating electron around a nucleus of hydrogen atom at the fundamental energy level is-

MCQ 27:
From rest a electron is accelerated between two such points which has potential 20 & 40 volts respectively. Associated Debroglie wavelength of electron is -

MCQ 28:
An electron microscope uses 40 KeV electrons. Find its resolving limit on the assumption that it is equal to the wavelength of the electron -

MCQ 29:
A hydrogen atom moving at a speed v absorbs a photon of wavelength 122 nm and stops. Find the value of v. (mass of hydrogen atom = 1.67 × 10–27 kg)

MCQ 30:
The de-broglie wavelength of an electron is 0.2 Å. Calculate the potential difference required to retard it to rest -

MCQ 31:
An α-particle and a singly ionized 4Be8 atom are accelerated through the same potential difference. Ratio of de-broglie wavelength-

MCQ 32:
The de-broglie wavelength of the electron in the second Bohr orbit is (given the radius of the first orbit r1 = 0.53 Å)

MCQ 33:
The de-Broglie wavelength associated with an electron having a kinetic energy of 10 eV is