CBSE 2025 · Region 7 · Set 1 · Q16 · 1 mark
Assertion (A) : The minimum negative potential applied to the anode in a photoelectric experiment at which photoelectric current becomes zero, is called cut-off voltage. Reason $\displaystyle (R)$ : The threshold frequency for a metal is the minimum frequency of incident radiation below which emission of photoelectrons does not take place.
Official answer
From CBSE’s own marking scheme for this paper.
(B)
Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
Dual Nature of Radiation and MatterExperimental Study of Photoelectric EffectUnderstandassertion_reasonmedium
More from Dual Nature of Radiation and Matter
- 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…2024 · asked 3×
- Assertion: Photoelectric current increases with an increase in intensity of incident radiation, for a given…2024 · asked 3×
- Figure shows the variation of photoelectric current measured in a photo cell circuit as a function of the…2023 · asked 3×
- Atomic spectral emission lines of hydrogen atom are incident on a zinc surface. The lines which can emit…2025 · asked 3×
- A beam of red light and a beam of blue light have equal intensities. Which of the following statements is…2025 · asked 3×
- Assertion: If accelerated electrons are passed through a narrow slit, a diffraction pattern is observed.…2026 · asked 3×
- Assertion: In photoelectric effect, the kinetic energy of the emitted photoelectrons increases with increase…2024 · asked 3×
- The figure shows v m^2 versus 1/(λ) graph for photoelectrons emitted from a surface where v m is the maximum…2023 · asked 3×
CBSE Class 12 Physics past-paper question from the 2025board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.