Hydrogen ( 1 H 1 ), Deuterium ( 1 H 2 ), singly ionised Helium ( 2 He 4 ) + and doubly ionised lithium ( 3 Li 6 ) ++ all have one electron around the nucleus. Consider an electron transition from n = 2 to n = 1 . If the wave lengths of emitted radiation are λ 1 , λ 2 , λ 3 and λ 4 respectively then approximately which one of the following is correct ?

4 λ 1 = 2 λ 2 = 2 λ 3 = λ 4

λ 1 = 2 λ 2 = 3 λ 3 = 4 λ 4

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IMPORTANT

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Half-lives of two radioactive elements $A$ and $B$ are $20 minutes$ and $40 minutes$ , respectively. Initially, the samples have an equal number of nuclei. After $80 minutes$ , the ratio of decayed numbers of $A$ and $B$ nuclei will be:

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Important Questions on Atoms and Nuclei

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JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 21 - Atoms and Nuclei>JEE Main - 4th April 2015>Q 85

As an electron makes a transition from an excited state to the ground state of a hydrogen-like atom/ion

HARD

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IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 21 - Atoms and Nuclei>JEE Main - 11th April 2015>Q 86

Let

N_{β}

be the number of

β

particle emitted by

1 gram

{Na}^{24}

radioactive nuclei having a half life of

15 h

. In

7.5 h

, the number

N_{β}

is close to

[N_{A} = 6 .023 \times 10^{23} {mole}^{- 1}]

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IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 21 - Atoms and Nuclei>JEE Main - 19th April 2014>Q 87

A piece of wood from a recently cut tree shows

20

decays per minute. A wooden piece of the same size placed in a museum (obtained from a tree cut many years back) shows

2

decays per minute. If the half-life of

C^{14}

5730 years

, then the age of the wooden piece placed in the museum is approximately
[This question was awarded a bonus and proper correction was made to avoid that]

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JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 21 - Atoms and Nuclei>JEE Main - 9th April 2014>Q 88

For which of the following particles will it be most difficult to experimentally verify the de-Broglie relationship?

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EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 21 - Atoms and Nuclei>JEE Main - 9th April 2014>Q 89

If the binding energy of the electron in a hydrogen atom is

13.6 eV

, the energy required to remove the electron from the first excited state of

{Li}^{+ +}

is :

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IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 21 - Atoms and Nuclei>JEE Main - 6th April 2014>Q 90

Hydrogen (₁H¹), Deuterium (₁H²), singly ionised Helium (₂He⁴)⁺ and doubly ionised lithium (₃Li⁶)⁺⁺ all have one electron around the nucleus. Consider an electron transition from

n = 2

n = 1

. If the wave lengths of emitted radiation are

λ_{1}, λ_{2}, λ_{3}

and

λ_{4}

respectively then approximately which one of the following is correct ?

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JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 21 - Atoms and Nuclei>JEE Main - 7th April 2013>Q 91

In a hydrogen like atom electron makes transition from an energy level with quantum number

n

to another with quantum number

(n - 1)

. If

n >> 1

, the frequency of radiation emitted is proportional to :

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EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 21 - Atoms and Nuclei>JEE Main - 12th January 2019 Shift 1>Q 92

A particle of mass

m

moves in a circular orbit in a central potential field

U (r) = \frac{1}{2} k r^{2} .

If Bohr's quantization conditions are applied, radii of possible orbitals and energy levels vary with quantum number

n

as:

Half-lives of two radioactive elements A and B are 20 minutes and 40 minutes, respectively. Initially, the samples have an equal number of nuclei. After 80 minutes, the ratio of decayed numbers of A and B nuclei will be:

Important Questions on Atoms and Nuclei

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Half-lives of two radioactive elements $A$ and $B$ are $20 minutes$ and $40 minutes$ , respectively. Initially, the samples have an equal number of nuclei. After $80 minutes$ , the ratio of decayed numbers of $A$ and $B$ nuclei will be: