Advertisements
Advertisements
प्रश्न
How does one explain the emission of electrons from a photosensitive surface with the help of Einstein’s photoelectric equation?
Advertisements
उत्तर १
Einstein’s Photoelectric equation is
KEmax = hv - hv0
eV0 = h(v - v0)
From above equation
Case - I:
If v > v0 [Emission with K.E.]
If v = v0 [Just emission]
If v < v0 [No emission]
उत्तर २
Einstein's photoelectric equation is, K. E = hv - Φ or hv = Φ + K. E.
This equation explains that when a photon of certain energy is incident on a photosensitive surface, a particular amount of energy gets used as a work function to eject electrons from their shells and the rest of the energy is acquired by ejected electrons as their Kinetic energy. The emission of electrons from a photosensitive surface takes place only if the incident energy of photons is greater than the work function.
संबंधित प्रश्न
In an experiment on the photoelectric effect, the slope of the cut-off voltage versus the frequency of incident light is found to be 4.12 × 10−15 Vs. Calculate the value of Planck’s constant.
A non-monochromatic light is used in an experiment on photoelectric effect. The stopping potential
In a photoelectric experiment, the collector plate is at 2.0 V with respect to the emitter plate made of copper (φ = 4.5 eV). The emitter is illuminated by a source of monochromatic light of wavelength 200 nm. Find the minimum and maximum kinetic energy of the photoelectrons reaching the collector.
Consider the situation of the previous problem. Consider the faster electron emitted parallel to the large metal plate. Find the displacement of this electron parallel to its initial velocity before it strikes the large metal plate.
(Use h = 6.63 × 10-34J-s = 4.14 × 10-15 eV-s, c = 3 × 108 m/s and me = 9.1 × 10-31kg)
Use Einstein’s photoelectric equation to show how from this graph,
(i) Threshold frequency, and (ii) Planck’s constant can be determined.
According to Einstein's photoelectric equation, the plot of the kinetic energy of the emitted photoelectrons from a metal versus the frequency of the incident radiation gives a straight line, whose slope ______.
Each photon has the same speed but different ______.
There are materials which absorb photons of shorter wavelength and emit photons of longer wavelength. Can there be stable substances which absorb photons of larger wavelength and emit light of shorter wavelength.
Radiation of frequency 1015 Hz is incident on three photosensitive surfaces A, B and C. Following observations are recorded:
Surface A: no photoemission occurs
Surface B: photoemission occurs but the photoelectrons have zero kinetic energy.
Surface C: photo emission occurs and photoelectrons have some kinetic energy.
Using Einstein’s photo-electric equation, explain the three observations.
The photon emitted during the de-excitation from the first excited level to the ground state of a hydrogen atom is used to irradiate a photocathode in which the stopping potential is 5 V. Calculate the work function of the cathode used.
