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Atoms · Question 11

JEE Main 2026 (Online) 21st January Evening ShiftMCQEasy📈 Topic in 35% papers+4−1
1

The energy of an electron in an orbit of the Bohr's atom is -0.04E0 eV where E0 is the ground state energy. If L is the angular momentum of the electron in this orbit and h is the Planck's constant, then 2 Lh is :

  1. 6
  2. 2
  3. 5
  4. 4

Answer

(3) 5

Solution

In Bohr's model: En = - E0n2 (here E0 = 13.6, the magnitude of the ground state energy in eV)

- E0n2 = -0.04E0

n2 = 10.04 = 25 n = 5

Bohr's quantisation: L = nh2

2 Lh = n = 5

Answer: (3)

JEE Main 2026 (Online) 21st January Evening Shift

Keep practising — Atoms

2

In a hydrogen like ion, the energy difference between the 2nd excitation energy state and ground is 108.8 eV. The atomic number of the ion is:

  1. 1
  2. 4
  3. 3
  4. 2
JEE Main 2025 (Online) 7th April Morning Shift
3

For a hydrogen atom, the ratio of the largest wavelength of Lyman series to that of the Balmer series is

  1. 5 : 27
  2. 27 : 5
  3. 3 : 4
  4. 5 : 36
JEE Main 2025 (Online) 7th April Morning Shift
4

Considering the Bohr model of hydrogen-like atoms, the ratio of the radius of 5th orbit of the electron in Li2+ and He+ is

  1. 32
  2. 23
  3. 49
  4. 94
JEE Main 2025 (Online) 4th April Morning Shift
5

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
JEE Main 2025 (Online) 4th April Evening Shift
6

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
7

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
8

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
9

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
10

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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