HARD

JEE Main

IMPORTANT

Earn 100

Consider the following statements:
$A$ . Atoms of each element emit characteristics spectrum.
$B .$ According to Bohr's Postulate, an electron in a hydrogen atom revolves in a certain stationary orbit.

$C .$ The density of nuclear matter depends on the size of the nucleus.
$D .$ A free neutron is stable but a free proton decay is possible.
$E .$ Radioactivity is an indication of the instability of nuclei. Choose the correct answer from the options given below.

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Important Questions on Atoms and Nuclei

HARD

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 21 - Atoms and Nuclei>JEE Main - 27 July 2021 Shift 2>Q 20

The

K_{α}

X-ray of molybdenum has wavelength

0.071 nm

. If the energy of a molybdenum atom with a

K

electron knocked out is

27.5 keV

, the energy of this atom when an

L

electron is knocked out will be

keV

. (Round off to the nearest integer )

[h = 4.14 \times 10^{- 15} eV s, c = 3 \times 10^{8} {m s}^{- 1}]

EASY

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 21 - Atoms and Nuclei>JEE Main 16 March 2021 Shift 1>Q 21

The first three spectral lines of

H

-atom in the Balmer series are given

λ_{1}, λ_{2}, λ_{3}

considering the Bohr atomic model, the wave lengths of first and third spectral lines

(\frac{λ_{1}}{λ_{3}})

are related by a factor of approximately

x

\times 10^{- 1}

. The value of

x

, to the nearest integer, is ________.

EASY

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 21 - Atoms and Nuclei>JEE Main 16 March 2021 Shift 2>Q 22

The half-life of

{Au}^{198}

2.7

days. The activity of

1.50 mg

{Au}^{198}

, if its atomic weight is

198 g {mol}^{- 1}

is,

(N_{A} = 6 \times 10^{23} {mol}^{- 1})

EASY

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 21 - Atoms and Nuclei>JEE Main 16 March 2021 Shift 2>Q 23

Calculate the time interval between

33 %

decay and

67 %

decay if half-life of a substance is

20 \min

EASY

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 21 - Atoms and Nuclei>JEE Main 17 March 2021 Shift 1>Q 24

If an electron is moving in the

n^{th}

orbit of the hydrogen atom, then its velocity

(v_{n})

for the

n^{th}

orbit is given as:

EASY

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 21 - Atoms and Nuclei>JEE Main 17 March 2021 Shift 1>Q 25

Which level of the single ionized carbon has the same energy as the ground state energy of hydrogen atom?

EASY

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 21 - Atoms and Nuclei>JEE Main 17 March 2021 Shift 2>Q 26

The atomic hydrogen emits a line spectrum consisting of various series. Which series of hydrogen atomic spectra is lying in the visible region?

HARD

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 21 - Atoms and Nuclei>JEE Main 17 March 2021 Shift 2>Q 27

A particle of mass

m

moves in a circular orbit in a central potential field

U (r) = U_{0} r^{4} .

If Bohr's quantization conditions are applied, radii of possible orbitals

r_{n}

vary with

n^{\frac{1}{α}}

, where

α

is _______ .

Important Questions on Atoms and Nuclei

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