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प्रश्न
Explain the concept of the photoelectric effect.
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उत्तर
- The phenomenon of emission of electrons from a metal surface, when radiation of appropriate frequency is incident on it, is known as the photoelectric effect.
- The emitted electrons are called photoelectrons and the resulting current in the circuit due to them is called photoelectric current.
- When ultraviolet radiations fall on the emitter plate, electrons are ejected from it.
- They are attracted towards the positive collector plate by the electric field. Thus, light falling on the surface of the emitter causes a current in the external circuit.
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संबंधित प्रश्न
What is the photoelectric effect?
Is it always possible to see the photoelectric effect with a red light?
The maximum kinetic energy of the photoelectrons depends only on ______
Define photoelectric effect.
If the total energy of radiation of frequency 1014 Hz is 6.63 J, Calculate the number of photons in the radiation.
The ratio of energies of photons produced due to transition of electron of hydrogen atom from its (i) second to first energy level and (ii) highest energy level to second level is respectively.
The following graph shows the stopping potential V0 versus frequency v for photoelectric emission from two metals A and B. The slope of each of the lines gives ______
When a photon enters glass from air, which one of the following quantity does not change?
The maximum velocity of the photoelectron emitted by the metal surface is 'v '. Charge and mass of the photoelectron is denoted by 'e' and 'm' respectively. The stopping potential in volt is ______.
The work function of a metal is 1.6 x 10-19 J. When the metal surface is illuminated by the light of wavelength 6400 Å, then the maximum kinetic energy of emitted photo-electrons will be (Planck's constant h = 6.4 x 10-34 Js) ____________.
In photoelectric experiment, if both the intensity and frequency of the incident light are doubled, then the saturation of photoelectric current ______.
The threshold frequency for a certain photosensitive metal is v0. When it is illuminated by light of frequency v = 2v0, the maximum velocity of photoelectrons is v0. What will be the maximum velocity of the photoelectrons when the same metal is illuminated by light of frequency
v = 5v0?
When a surface 1 cm thick is illuminated by light of wavelength 'λ', the stopping potential is 'V0'. When the same surface is illuminated by light of wavelength '3λ', the stopping potential is `"V"_0/6`. The threshold wavelength for the metallic surface is ______.
Light of different frequencies, whose photons have energies 3 eV and 18 eV respectively, successively illuminate a metal of work function 2 eV. The ratio of the maximum speeds of the emitted electrons will be ______.
The photon of frequency vis incident on a metal surface whose threshold frequency is v0. The kinetic energy of the emitted photoelectrons will be ____________.
The photon of frequency vis incident on a metal surface whose threshold frequency is v0. The kinetic energy of the emitted photoelectrons will be ______.
When light of wavelength '`lambda`' is incident on photosensitive surface, photons of power 'P' are emitted. The number of photons (n) emitted in 't' second is (h = Planck's constant, c = velocity of light in vacuum) ____________.
When radiation of wavelength λ is used to illuminate a metallic surface, the stopping potential is V. When the same surface is illuminated with radiation of wavelength 3λ, the stopping potential is `"V"/4`. If the threshold wavelength for the metallic surface is nλ. then value of n will be ______.
Photoelectrons are observed to just emit out of a material surface when the light of 620 nm falls on it with the intensity of 100 W m-2. If the light of wavelength 400 nm is incident on the same material with an intensity of 1 W m-2, what would be the minimum reverse potential needed to stop the outflow of the electrons?
The radiation emitted, when an electron jumps from n = 3 to n = 2 orbit is a hydrogen atom, falls on a metal to produce photoelectron. The electrons from the metal surface with maximum kinetic energy are made to move perpendicular to a magnetic field of `1/320`T in a radius of 10-3m. Find the 320 work function of metal:
We wish to observe an object which is 2.5Å in size. The minimum energy photon that can be used ______.
A point isotropic light source of power P = 12 watts is located on the axis of a circular mirror of radius R = 3 cm. If the distance of the source from the centre of the mirror is a = 39 cm and the reflection coefficient of the mirror is α = 0.70 then the force exerted by the light ray on the mirror is ______ × 10-10 N.
Light of wavelength λ, which is less than threshold wavelength is incident on a photosensitive material. If incident wavelength is decreased so that emitted photoelectrons are moving with same velocity, then stopping potential will ______.
Give Einstein's explanation of the photoelectric effect.
Draw a neat labelled diagram of photo-current as a function of accelerating potential for fixed incident intensity but different incident frequencies for the same emitter material.
