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प्रश्न
The electrons are emitted in the photoelectric effect from a metal surface.
पर्याय
only if the frequency of radiation is above a certain threshold value.
only if the temperature of the surface is high.
at the that is independent of the nature of metal.
with a maximum velocity proportional to the frequency of incident radiation
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उत्तर
The electrons are emitted in the photoelectric effect from a metal surface only if the frequency of radiation is above a certain threshold value.
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संबंधित प्रश्न
Is it always possible to see the photoelectric effect with a red light?
Using the values of work function given in the following table, tell which metal will require the highest frequency of incident radiation to generate photocurrent.
Typical values of work function for some common metals
| Metal | Work function (in eV) |
| Potassium | 2.3 |
| Sodium | 2.4 |
| Calcium | 2.9 |
| Zinc | 3.6 |
| Silver | 4.3 |
| Aluminium | 4.3 |
| Tungsten | 4.5 |
| Copper | 4.7 |
| Nickel | 5.0 |
| Gold | 5.1 |
It is observed in an experiment on the photoelectric effect that an increase in the intensity of the incident radiation does not change the maximum kinetic energy of the electrons. Where does the extra energy of the incident radiation go? Is it lost? State your answer with explanatory reasoning.
The maximum kinetic energy of the photoelectrons depends only on ______
The minimum frequency for photoelectric effect on metal is 7 × 1014 Hz, Find the work function of the metal.
Explain the concept of the photoelectric effect.
If the total energy of radiation of frequency 1014 Hz is 6.63 J, Calculate the number of photons in the radiation.
With the help of a circuit diagram describing an experiment to study the photoelectric effect.
The energy of the incident photon on the metal surface is 3 W and then 5 W, where W is the work function for that metal. The ratio of velocities of emitted photoelectrons is ______.
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 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?
The work function of a substance is 4.0 eV. The longest wavelength of light that can cause photo-emission from this substance is approximately (h = 6.63 × 10-34 Js)[1eV = 1.6 × 10-19 J]
The lowest frequency of light that will cause the emission of photoelectrons from the surface of a metal (for which work function is 1.65 eV) will be ____________.
Which one of the following statements ts INCORRECT for stopping potential in photoelectric emission?
When a certain metallic surface is illuminated with monochromatic light of wavelength '`lambda`', the stopping potential for photoelectric effect is '3V0'. If the same surface is illuminated with a light of wavelength '`2 lambda`', the stopping potential is found as 'V0'. The threshold wavelength for this surface is ____________.
Two incident radiations having energies two times and ten times of the work function of a metal surface, produce photoelectric effect. The ratio of maximum velocities of emitted photo electrons respectively is ____________.
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) ____________.
The ratio of slopes m1: ro2 of the lines given in the following graphs is, ______.
A light of frequency 'v' is incident on the metal surface whose threshold frequency is 'v0'. If v = v0, then [c = speed of light in medium] ____________.
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 ______.
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.
Two radiations of photons energies 1 eV and 2.5 eV, successively illuminate a photosensitive metallic surface of work function 0.5 eV. The ratio of the maximum speeds of the emitted electrons is ______.
Light of two different frequencies whose photons have energies 1.3 eV and 2.8 eV respectively, successfully illuminate a metallic surface whose work function is 0.8 eV. The ratio of maximum speeds of emitted electrons will be ______.
Photoelectric emission is observed from a metallic surface for frequencies ν1 and ν2 of the incident light rays (ν1 > ν2). If the ratio of the maximum value of the kinetic energy of the photoelectrons emitted in the first case to that in the second case is 2 : K, then the threshold frequency of the metallic surface is ______.
When monochromatic light of frequency v1 falls on a metal surface, the stopping potential required is found to be V1. If the radiation of frequency v2 is incident on the surface, the stopping potential required V2 is ______. (v2 > v1)
Explain the failure of wave theory of light to account for the observations from experiments on photoelectric effect.
Give Einstein's explanation of the photoelectric effect.
