Atoms and Nuclei Practice Questions
JEE · Physics · 1567 free MCQs with instant results and detailed explanations.
1567
Total
320
Easy
712
Medium
535
Hard
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Topics in Atoms and Nuclei
Bohr Model
169
Hydrogen Spectrum
182
X-Rays
211
Nuclear Structure
194
Radioactivity
203
Binding Energy
217
Nuclear Fission and Fusion
227
Mass-Energy Equivalence
164
Sample Questions from Atoms and Nuclei
Here are 10 sample questions. Start a quiz to get randomized questions with scoring.
Q1
Easy
In the Bohr model of the hydrogen atom, what is the relationship between the radius of the nth orbit and the principal quantum number n?
A.
r ā n^2
B.
r ā n
C.
r ā 1/n
D.
r ā n^3
Show Answer & Explanation
Correct Answer: A
According to the Bohr model, the radius of the nth orbit of an electron in a hydrogen atom is proportional to the square of the principal quantum number n, hence r ā n^2.
Q2
Easy
In the context of the Bohr model, which of the following statements about angular momentum of an electron in a hydrogen atom is correct?
A.
It is quantized and is an integral multiple of h/2Ļ.
B.
It is not quantized and can take any value.
C.
It is quantized and is an integral multiple of h.
D.
It is zero for all orbits.
Show Answer & Explanation
Correct Answer: A
In the Bohr model, the angular momentum of an electron in an orbit is given by L = n(h/2Ļ), which shows that it is quantized and must be an integral multiple of h/2Ļ.
Q3
Easy
Which of the following statements is true about the energy levels in a hydrogen atom according to the Bohr model?
A.
Energy levels are quantized.
B.
Energy levels are continuous.
C.
Energy levels are only for electrons in motion.
D.
Energy levels depend on the mass of the nucleus.
Show Answer & Explanation
Correct Answer: A
In the Bohr model, the energy levels of electrons in an atom are quantized, meaning electrons can only occupy certain discrete energy levels.
Q4
Medium
According to the Bohr model, what is the angular momentum of an electron in the second orbit of a hydrogen atom?
A.
h/2Ļ
B.
h
C.
2h/Ļ
D.
3h/2Ļ
Show Answer & Explanation
Correct Answer: A
The angular momentum L of an electron in the nth orbit is given by L = n*h/2Ļ. For n=2, L = 2*h/2Ļ = h/Ļ.
Q5
Medium
Which of the following transitions in a hydrogen atom will emit the highest energy photon?
A.
n=3 to n=2
B.
n=4 to n=3
C.
n=2 to n=1
D.
n=5 to n=4
Show Answer & Explanation
Correct Answer: C
The energy of the emitted photon corresponds to the difference in energy levels. A transition from n=2 to n=1 results in the greatest energy difference.
Q6
Medium
According to the Bohr model, which quantum number determines the energy level of an electron in a hydrogen atom?
A.
Azimuthal quantum number
B.
Principal quantum number
C.
Magnetic quantum number
D.
Spin quantum number
Show Answer & Explanation
Correct Answer: B
The principal quantum number (n) determines the energy level of an electron in the Bohr model. Higher n corresponds to higher energy.
Q7
Medium
What effect does increasing the atomic number Z have on the radius of a hydrogen-like atom according to the Bohr model?
A.
Increases the radius
B.
Decreases the radius
C.
No effect
D.
Increases then decreases
Show Answer & Explanation
Correct Answer: B
According to the Bohr model, the radius of a hydrogen-like atom is inversely proportional to Z; as Z increases, the radius decreases.
Q8
Hard
What is the energy of the first excited state of a hydrogen atom according to the Bohr model?
A.
-3.4 eV
B.
-1.51 eV
C.
-13.6 eV
D.
0 eV
Show Answer & Explanation
Correct Answer: A
The energy of the nth level in the hydrogen atom is given by E_n = -13.6/nĀ² eV. For n=2, E_2 = -13.6/2Ā² = -3.4 eV.
Q9
Hard
In the Bohr model, if an electron moves from n=4 to n=2, what is the frequency of the emitted photon?
A.
6.9 x 10^14 Hz
B.
4.5 x 10^14 Hz
C.
7.5 x 10^13 Hz
D.
3.2 x 10^15 Hz
Show Answer & Explanation
Correct Answer: A
The frequency can be calculated using the energy difference for the transition, yielding approximately 6.9 x 10^14 Hz.
Q10
Hard
According to the Bohr model, which of the following transitions in a hydrogen atom results in the emission of the highest energy photon?
A.
n=5 to n=1
B.
n=3 to n=2
C.
n=4 to n=3
D.
n=2 to n=1
Show Answer & Explanation
Correct Answer: A
The energy emitted during transitions is highest when the electron moves to the lowest energy level from the highest, hence n=5 to n=1.
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Atoms and Nuclei ā JEE Physics Practice Questions Online
This page contains 1567 practice MCQs for the chapter Atoms and Nuclei in JEE Physics. The questions are organized by difficulty ā 320 easy, 712 medium, 535 hard ā so you can choose the right level for your preparation.
Every question includes a detailed explanation to help you understand the concept, not just memorize answers. Take a timed quiz to simulate exam conditions, or practice at your own pace with no time limit. This chapter covers 8 topics, giving you comprehensive coverage of the entire chapter.