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Atoms · Question 15

JEE Main 2025 (Online) 4th April Evening ShiftMCQEasy📈 Topic in 35% papers+4−1
1

Given below are two statements : In the light of the above statements, choose the most appropriate answer from the options given below :

  1. Both Statement I and Statement II are correct
  2. Statement I is correct but Statement II is incorrect
  3. Both Statement I and Statement II are incorrect
  4. Statement I is incorrect but Statement II is correct

Answer

(2) Statement I is correct but Statement II is incorrect

Solution

Statement I: E = h [h] = [E][ ] = [ ML2T-2][ T-1] = [ ML2T-1]

Angular momentum L = mvr [L] = [M][ LT-1][L] = [ ML2T-1]

Same dimensions. Correct.

Statement II: As per NCERT (Bohr's second postulate), the electron revolves only in those orbits for which the angular momentum is an integral multiple of h2 , i.e. mvr = nh2 — not an integral multiple of h. Incorrect.

Answer: (2)

JEE Main 2025 (Online) 4th April Evening Shift

Keep practising — Atoms

2

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R. In the light of the above statements, choose the correct answer from the options given below

  1. A is true but R is false
  2. Both A and R are true and R is the correct explanation of A
  3. A is false but R is true
  4. Both A and R are true but R is NOT the correct explanation of A
JEE Main 2025 (Online) 3rd April Evening Shift
3

An electron in the hydrogen atom initially in the fourth excited state makes a transition to nth energy state by emitting a photon of energy 2.86 eV. The integer value of n will be .

JEE Main 2025 (Online) 3rd April Evening Shift
4

Considering Bohr's atomic model for hydrogen atom : Choose the correct answer from the options given below :

  1. (A), (B) only
  2. (A), (D) only
  3. (A), (C) only
  4. (B), (D) only
JEE Main 2025 (Online) 2nd April Morning Shift
5

Assuming the validity of Bohr's atomic model for hydrogen-like ions the radius of Li++ ion in its ground state is given by 1Xa0, where X = (Where a0 is the first Bohr's radius.)

  1. 2
  2. 9
  3. 1
  4. 3
JEE Main 2025 (Online) 2nd April Evening Shift
6

The frequency of revolution of the electron in Bohr's orbit varies with n, the principal quantum number as:

  1. 1n4
  2. 1n2
  3. 1n3
  4. 1n
JEE Main 2025 (Online) 28th January Evening Shift

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