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प्रश्न
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.
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उत्तर
In the photoelectric effect, stopping potential is directly proportional to the maximum kinetic energy of the emitted electron.
This maximum kinetic energy is further dependent on the frequency of incident light as well as the work function of the cathode. Combining both these facts, we can arrive at the work function of the cathode used.
KE = hν - Φ0
Where, hν = E2 - E1
= `(-13.6)/2^2 - (-13.6)/1^2`
= `3/4 xx 13.6 = 10.2` eV
eV = hν - Φ0
`5V xx e = 10.2 eV - phi_0`
Φ0 = 5.2 eV
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संबंधित प्रश्न
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A non-monochromatic light is used in an experiment on photoelectric effect. The stopping potential
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(Use h = 6.63 × 10-34J-s = 4.14 × 10-15 eV-s, c = 3 × 108 m/s and me = 9.1 × 10-31kg)
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(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,
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How does one explain the emission of electrons from a photosensitive surface with the help of Einstein’s photoelectric equation?
Each photon has the same speed but different ______.
A student performs an experiment on photoelectric effect, using two materials A and B. A plot of Vstop vs ν is given in Figure.
- Which material A or B has a higher work function?
- Given the electric charge of an electron = 1.6 × 10–19 C, find the value of h obtained from the experiment for both A and B.
Comment on whether it is consistent with Einstein’s theory:
If c is the velocity of light in free space, the correct statements about photon among the following are:
- The energy of a photon is E = hv.
- The velocity of a photon is c.
- The momentum of a photon, ρ = `(h v)/c`.
- In a photon-electron collision, both total energy and total momentum are conserved.
- Photon possesses positive charge.
Choose the correct answer from the options given below:
