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Friday, 9 October

JEE Main 2024 · PhysicsMultiple choiceSingle correctMediumCalculation

JEE Main 31 January 2024, Shift 1, Physics Q46

Question 46 of 90 in this shift, Physics question 16 of 30, Section A.

When a metal surface is illuminated by light of wavelength λ\lambda, the stopping potential is 8V. When the same surface is illuminated by light of wavelength 3λ3\lambda, stopping potential is 2V. The threshold wavelength for this surface is:
  1. (1)4.5λ4.5\lambda
  2. (2)3λ3\lambda
  3. (3)5λ5\lambda
  4. (4)9λ9\lambdaOfficial answer

Official answer

Option 4

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 3× in all
  1. 2 Apr 2026, Shift 1 · Q42For a certain metal, when monochromatic light of wavelength λ\lambda is incident, the stopping potential for photoelectrons is 3Vo3V_o.…MediumSingle correct
  2. 11 Apr 2023, Shift 1 · Q34A metallic surface is illuminated with radiation of wavelength λ\lambda, the stopping potential is V0V_0. If the same surface is…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 42 of the 174 JEE Main shifts held from 2017 to 2026.