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Saturday, 31 October

JEE Main 2021 · PhysicsMultiple choiceSingle correctEasyCalculation

JEE Main 22 July 2021, Shift 2, Physics Q19

Question 19 of 90 in this shift, Physics question 19 of 30, Section A.

A nucleus with mass number 184 initially at rest emits an α-particle. If the Q value of the reaction is 5.5 MeV, calculate the kinetic energy of the α-particle.
  1. (1)0.12 MeV
  2. (2)5.38 MeVOfficial answer
  3. (3)5.0 MeV
  4. (4)5.5 MeV

Official answer

Option 2

NTA final key.

Chapter
Nuclei
Topic
Radioactive Decay
Idea tested
Alpha Decay Kinematics and Q-Value

Same idea in other shifts

Asked 2× in all
  1. 8 Apr 2026, Shift 2 · Q44Two radioactive substances A and B of mass numbers 200 and 212 respectively, shows spontaneous α\alpha-decay with same QQ value of 1…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.