Advertisements
Advertisements
प्रश्न
Is it always necessary to use red light to get a photoelectric effect?
Advertisements
उत्तर
No, the broad wavelength and low energy of red light, photons do not have sufficient energy to pull an electron out of its orbital.
APPEARS IN
संबंधित प्रश्न
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?
If the total energy of radiation of frequency 1014 Hz is 6.63 J, Calculate the number of photons in the radiation.
What is the photoelectric effect? Define stopping potential and photoelectric work function.
The energy of a photon is 2 eV. Find its frequency and wavelength.
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 ______
Threshold frequency for a metal is 1015 Hz. Light of `lambda` = 4000 Å falls on its surface. Which of the following statements is correct?
A metal surface is illuminated by light of given intensity and frequency to cause photoemission. If the intensity of illumination is reduced to one-fourth of its original value then the maximum KE of the emitted photoelectrons would be ______.
In photoelectric effect, graph of saturation current versus frequency of light is plotted. The nature of the graph will be ____________.
When wavelength of incident radiation on the metal surface is reduced from 'λ1' to 'λ2', the kinetic energy of emitted photoelectrons is tripled. The work function of the metal is ______.
(h = Planck's constant, c =velocity of light)
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 photon of frequency vis incident on a metal surface whose threshold frequency is v0. The kinetic energy of the emitted photoelectrons will be ____________.
Following graphs show the variation of stopping potential corresponding to the frequency of incident radiation (F) for a given metal. The correct variation is shown in graph (v0 = Threshold frequency).
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?
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 ____________.
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 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] ____________.
In experiment of photoelectric effect, the stopping potential for incident yellow light of wavelength 5890 Å is 4 volt. If the yellow light is replaced by blue light of wavelength 4000 Å, the stopping potential is ____________.
The radiation corresponding to the 3 → 2 transition of a hydrogen atom falls on a gold surface to generate photoelectrons. These electrons are passed through a magnetic field of 5 × 10-4 T. Assume that the radius of the largest circular path followed by these electrons is 7 mm, and the work function of the metal is ______.
(Mass of electron = 9.1 × 10-31 kg)
When ultraviolet light of wavelength 100 nm is incident upon a sample of silver metal, a potential difference of 7.7 volt is required to stop the photoelectrons from reaching the collector plate. The potential required to stop photo electrons when light of wavelength 200 nm is incident upon silver is ______.
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 ______.
If the electron in hydrogen atom jumps from second Bohr orbit to ground state and difference between energies of the two states is radiated in the form of photons. If the work function of the material is 4.2 eV, then stopping potential is ______.
[Energy of electron in nth orbit = `-13.6/"n"^2` eV ]
The photoelectric threshold for a certain metal surface is 3600 Å. If the metal surface is irradiated by a wavelength of 1100 Å, then kinetic energy of the emitted photoelectrons is ______.
If the maximum kinetic energy of emitted electrons in the photoelectric effect is 2eV, the stopping potential will be ______.
By increasing the voltage in an electron diffraction tube, the radius of the diffraction rings will ______.
A parallel plate capacitor with air between the plates has capacitance 9 pF. The separation between the plates becomes thrice and the space between them is filled with a medium of dielectric constant 6. The capacitance becomes 'x' pF. The value of 'x' is ______.
