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प्रश्न
Define 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.
संबंधित प्रश्न
Choose the correct option.
Polychromatic (containing many different frequencies) radiation is used in an experiment on the photoelectric effect. The stopping potential ______.
Photocurrent recorded in the microammeter in an experimental setup of the photoelectric effect vanishes when the retarding potential is more than 0.8 V if the wavelength of incident radiation is 4950 Å. If the source of incident radiation is changed, the stopping potential turns out to be 1.2 V. Find the work function of the cathode material and the wavelength of the second source.
The threshold wavelength of tungsten is 2.76 x 10-5 cm.
(a) Explain why no photoelectrons are emitted when the wavelength is more than 2.76 x 10-5 cm.
(b) What will be the maximum kinetic energy of electrons ejected in each of the following cases
(i) if ultraviolet radiation of wavelength λ = 1.80 × 10-5 cm and
(ii) radiation of frequency 4 x 1015 Hz is made incident on the tungsten surface?
Radiation of wavelength 4500 Å is incident on a metal having work function 2.0 eV. Due to the presence of a magnetic field B, the most energetic photoelectrons emitted in a direction perpendicular to the field move along a circular path of radius 20 cm. What is the value of the magnetic field B?
As the intensity of incident light increases ______
Find the energy of photon which have momentum 2 × 10-16 gm-cm/sec.
The energy of a photon is 2 eV. Find its frequency and wavelength.
With the help of a circuit diagram describe the experiment to study the characteristics of the photoelectric effect. Hence discuss any 2 characteristics of the photoelectric effect.
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 ______
The graph of stopping potential `"V"_"s"` against frequency v of incident radiation is plotted for two different metals P and Q as shown in the graph. ΦP and ΦQ are work-functions of P and Q respectively, then
The work function of a metallic surface is 5.01 eV. The photoelectrons are emitted when light of wavelength 2000 Å falls on it. The potential difference applied to stop the fastest photoelectrons is [h = 4.14 x 10-15 eV sec] ____________.
In photoelectric experiment, if both the intensity and frequency of the incident light are doubled, then the saturation of photoelectric current ______.
Light of frequency 2 times the threshold frequency is incident on a photo sensitive material. If the frequency is made `1/3`rd and intensity is doubled then the photocurrent will ______.
The photo electric effect to take place for a metal, the minimum frequency required is 5.792 × 1014 Hz. A light of wavelength 6000 Å is incident on that metal surface. What is the corresponding frequency of light and will there be photoelectric emissions? [velocity of light = 3 × 108 m/s]
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 ____________.
The radiations of energies 1 eV and 2.5 eV are incident on a metal surface having work function 0.5 eV. The ratio of the maximum velocities of the emitted photo-electrons is ____________.
When a metal with work function 0.6 eV is illuminated with light of energy 2 eV, the stopping potential will be ____________.
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 ____________.
A metal surface having work function 'w0' emits photoelectrons when photons of energy 'E' are incident on it. The electron enters the uniform magnetic field (B) in perpendicular direction and moves in circular path of radius 'r'. Then 'r' is equal to (m and e be the mass and charge of electron respectively) ____________.
The stopping potential in the context of photoelectric effect depends on the following property of incident electromagnetic radiation ______.
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?
We wish to observe an object which is 2.5Å in size. The minimum energy photon that can be used ______.
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 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 ______.
If the maximum kinetic energy of emitted electrons in the photoelectric effect is 2eV, the stopping potential will be ______.
Explain the formation of clouds at high altitude.
Light of wavelength 'λ' falls on a metal having work function \[\frac {hc}{λ_0}\]. Photoelectric effect will take place only if (λ0 is the threshold wavelength) ______.
