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Saturday, 31 October

JEE Main 2023 · ChemistryNumerical answerNumerical valueEasyCalculation

JEE Main 12 April 2023, Shift 1, Chemistry Q82

Question 82 of 90 in this shift, Chemistry question 22 of 30, Section B.

Values of work function (W0W_0) for a few metals are given below Metal: Li, Na, K, Mg, Cu, Ag W0W_0/eV: 2.42, 2.3, 2.25, 3.7, 4.8, 4.3 The number of metals which will show photoelectric effect when light of wavelength 400nm falls on it is _______ Given: h = 6.6×10−346.6 \times 10^{-34} J s c = 3×1083 \times 10^8 m s−1^{-1} e = 1.6×10−191.6 \times 10^{-19} C

The figure, in words

Table with metals Li, Na, K, Mg, Cu, Ag and work functions W0/eV 2.42, 2.3, 2.25, 3.7, 4.8, 4.3 respectively.

Official answer

3

NTA final key.

Chapter
Structure of Atom
Topic
Bohr's Atomic Theory
Idea tested
Photoelectric Effect Coupling

Same idea in other shifts

Asked 3× in all
  1. 2 Apr 2026, Shift 2 · Q71The surface of sodium metal is irradiated with radiation of wavelength xx nm. The kinetic energy of ejected electrons is…EasyNumerical value
  2. 2 Sep 2020, Shift 2 · Q46The work function of sodium metal is 4.41×10−194.41\times10^{-19} J. If photons of wavelength 300 nm are incident on the metal, the kinetic energy…EasyNumerical value

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. This question needs a figure we do not reproduce; it is described in words above. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.