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Friday, 9 October

JEE Main 2025 · PhysicsMultiple choiceAssertion–reasonEasyConceptual

JEE Main 7 April 2025, Shift 2, Physics Q44

Question 44 of 75 in this shift, Physics question 19 of 25, Section A.

Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : The density of the copper (2964Cu)\left({}^{64}_{29}\mathrm{Cu}\right) nucleus is greater than that of the carbon (612C)\left({}^{12}_{6}\mathrm{C}\right) nucleus. Reason (R) : The nucleus of mass number AA has a radius proportional to A1/3A^{1/3}. In the light of the above statements, choose the most appropriate answer from the options given below :
  1. (1)Both (A) and (R) are correct and (R) is the correct explanation of (A)
  2. (2)Both (A) and (R) are correct but (R) is not the correct explanation of (A)
  3. (3)(A) is correct but (R) is not correct
  4. (4)(A) is not correct but (R) is correctOfficial answer

Official answer

Option 4

NTA final key.

Chapter
Nuclei
Topic
Nuclear Binding Energy
Idea tested
Nuclear Radius and Density

Same idea in other shifts

Asked 4× in all
  1. 8 Apr 2025, Shift 2 · Q44For a nucleus of mass number A and radius R, the mass density of nucleus can be represented asEasySingle correct
  2. 31 Jan 2024, Shift 2 · Q47The mass number of nucleus having radius equal to half of the radius of nucleus with mass number 192 is:EasySingle correct
  3. 31 Jan 2024, Shift 2 · Q60A nucleus has mass number A1A_1 and volume V1V_1. Another nucleus has mass number A2A_2 and Volume V2V_2. If relation between mass number…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. Lumi analyses 42 of the 174 JEE Main shifts held from 2017 to 2026.