✓ Board-verified
Physics · 2023 · 4 marks
Dual Nature of Radiation and MatterEinstein’s Photoelectric Equation: Energy Quantum of Radiation4 marksAnalysecase study
CBSE 2023 · Region 2 · Set 2 · Q34
(a) Figure shows the variation of photoelectric current measured in a photo cell circuit as a function of the potential difference between the plates…
Figure shows the variation of photoelectric current measured in a photo cell circuit as a function of the potential difference between the plates of the photo cell when light beams $\displaystyle \mathrm{A}, \mathrm{B}, \mathrm{C}$ and D of different wavelengths are incident on the photo cell. Examine the given figure and answer the following questions:
Potential Difference
(i)
Which light beam has the highest frequency and why ?
(ii)
Which light beam has the longest wavelength and why?
(iii)
Which light beam ejects photoelectrons with maximum momentum and why?
What is the effect on threshold frequency and stopping potential on increasing the frequency of incident beam of light ? Justify your answer.
Marking-scheme solution
(iii) Identification of beam ejecting photoelectrons with maximum momentum and reason OR
(b) Effect on threshold frequency and stopping potential on the increasing frequencv and iustification - $\displaystyle 1$+$\displaystyle 1$
(i) The light beam B because it requires maximum retarding potential to reduce the photoelectric current to zero.
(ii) The light beam C because it requires minimum retarding potential to reduce photoelectric current to zero.
(iii) The light beam B ejects photoelectrons with maximum momentum. because highest frequency light beam ejects photoelectrons with highest kinetic energy and hence highest momentum.
There is no effect on threshold frequency since it is characteristic of the metal.
With increase in freqquency of incidents beam of light , stopping potential increases because to stop the photoelectrons of higher kinetic energy, larger retarding potential is required.
\[e V_{0}=h\left(v-v_{0}\right)
\]
All Dual Nature of Radiation and Matter questions2023 question paperNCERT solutions: Dual Nature of Radiation and MatterPractice Dual Nature of Radiation and Matter →
More from Dual Nature of Radiation and Matter
- The de-Broglie wavelength associated with an electron is 0.30 nm. Calculate: the speed, and the kinetic energy (in eV), of the electron.2022
- In a photoelectric experiment, the emitter plate is irradiated with radiation of 200 nm. The photocurrent becomes zero when the collector plate…2026
- Draw a plot of frequency v of incident radiations as a function of stopping potential V_0 for a given photo emissive material. What information can…2025
- A particle is associated with a de Broglie wave of wavelength 1.2 nm. The kinetic energy of the particle is made four times. Calculate the new value…2023
- de Broglie wavelength λ as a function of 1/(√ K), for two particles of masses m_1 and m_2 are shown in the figure. Here, K is the energy of the…2024
- The energy of a photon of wavelength 663 nm is2023
- Consider a neutron (mass m ) of kinetic energy E and a photon of the same energy. Let λ_n and λ_p be the de Broglie wavelength of neutron and the…2024
- Mention any three features of results of experiment on photoelectric effect which cannot be explained using the wave theory of light. In his…2025
CBSE Class 12 Physics past-paper question from the 2023 board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.