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Friday, 9 October

JEE Main 2026 · PhysicsMultiple choiceSingle correctMediumCalculation

JEE Main 2 April 2026, Shift 1, Physics Q42

Question 42 of 75 in this shift, Physics question 17 of 25, Section A.

For a certain metal, when monochromatic light of wavelength λ\lambda is incident, the stopping potential for photoelectrons is 3Vo3V_o. When the same metal is illuminated by light of wavelength 2λ2\lambda, then the stopping potential becomes VoV_o. The threshold wavelength for photoelectric emission for the given metal is αλ\alpha\lambda. The value of α\alpha is _______.
  1. (1)11
  2. (2)44Official answer
  3. (3)22
  4. (4)33

Official answer

Option 2

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. 31 Jan 2024, Shift 1 · Q46When a metal surface is illuminated by light of wavelength λ\lambda, the stopping potential is 8V. When the same surface is illuminated…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.