JEE Main 2021 · PhysicsMultiple choiceSingle correctMediumCalculation

JEE Main 25 February 2021, Shift 2, Physics Q13

Question 13 of 90 in this shift, Physics question 13 of 30, Section A.

The stopping potential for electrons emitted from a photosensitive surface illuminated by light of wavelength 491 nm is 0.710 V. When the incident wavelength is changed to a new value, the stopping potential is 1.43 V. The new wavelength is :

(1)309 nm
(2)329 nm
(3)382 nmOfficial answer
(4)400 nm

Official answer

Option 3

NTA final key.

Chapter: Dual Nature of Radiation and Matter
Topic: Photoelectric Effect
Idea tested: Two-Wavelength System of Equations

Same idea in other shifts

Asked 7× in all

2 Apr 2026, Shift 1 · Q42For a certain metal, when monochromatic light of wavelength $\lambda$ is incident, the stopping potential for photoelectrons is $3V_o$ .…MediumSingle correct
31 Jan 2024, Shift 1 · Q46When a metal surface is illuminated by light of wavelength $\lambda$ , the stopping potential is 8V. When the same surface is illuminated…MediumSingle correct
11 Apr 2023, Shift 1 · Q34A metallic surface is illuminated with radiation of wavelength $\lambda$ , the stopping potential is $V_0$ . If the same surface is…MediumSingle correct
4 Aug 2021, Shift 2 · Q3Two wavelengths $\lambda_1=496\,\mathrm{nm}$ and $\lambda_2=620\,\mathrm{nm}$ fall on a metal surface. Calculate the work function if the…MediumSingle correct
25 Jul 2021, Shift 2 · Q18When radiation of wavelength $\lambda$ is incident on a metallic surface, the stopping potential of ejected photoelectrons is 4.8 V. If…MediumSingle correct
3 Sep 2020, Shift 1 · Q18When the wavelength of radiation falling on a metal is changed from 500 nm to 200 nm, the maximum kinetic energy of the photoelectrons…MediumSingle correct

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.