Physics

Nuclear and Atomic Physics

571 Questions

Nuclear and atomic physics explores the components and properties of the nucleus, including isotopes, radioactive decay, and fundamental forces. These concepts are essential for various competitive exams requiring a strong foundation in physics. The provided questions cover structural properties, mass, energy equivalence, and particle interactions.

Nucleus propertiesIsotopes and mass numberAlpha particle scatteringNuclear forcesMass energy equivalenceBeta particle emission

Nuclear and Atomic Physics Questions

Multiple choice chemistry structure of the atom neutrons discovery of neutrons structure of atoms

The lightest particle is/are :

  1. electron

  2. proton

  3. neutron
  4. $\beta$-particle
Reveal answer Fill a bubble to check yourself
A,D Correct answer
Explanation
The electron is the lightest particle of the atom. It has a mass of $ 9.1 \times 10^{-28}$ grams. Comparing this mass to that of the proton's at $1.6726 \times 10^{-24}$ grams, an electron is nearly $0.0005$ times the proton's mass.

Beta particles are high-energy, high-speed electrons or positrons emitted by certain types of radioactive nuclei. Hence, their mass will similar to that of the electron.

Hence, options A and D are correct.
Multiple choice chemistry structure of the atom neutrons discovery of neutrons structure of atoms

Assertion : Protons are better projectiles than neutrons.
Reason : The neurons being neutral do not experience repulsion from positively charged nucleus.

  1. If both (A) and (R) are correct, and (R) is the correct explanation of (A).

  2. If both (A) and (R) are correct, but (R) is not the correct explanation of (A).

  3. If (A) is correct, but (R) is correct.

  4. If (A) is incorrect, but (R) is correct.

  5. If both (A) and (R) are incorrect.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Neutrons are better projectiles than protons.
The decreasing order of the projectile power is $\displaystyle _0n^1 > _{1}H^{1} > _{1}H^{2}> _{2}He^{4}$
The neurons being neutral do not experience repulsion from positively charged nucleus.
Thus, (A) is incorrect, but (R) is correct.

Multiple choice chemistry structure of the atom neutrons discovery of neutrons structure of atoms

Arrange the following particle in increasing order of values of e/m ratio : electron (e), proton (p), neutron (n) and $\displaystyle \alpha $-particle $\displaystyle (\alpha) $.

  1. n, p, e, $\displaystyle \alpha $
  2. n, $\displaystyle \alpha $, p, e
  3. n, p, $\displaystyle \alpha $, e
  4. e, p, n, $\displaystyle \alpha $
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

$\displaystyle n< \alpha < p< e$            

e/m of n = 0
$\displaystyle e/m: : of: : \alpha =\frac{9.58\times 10^{4}}{2}c/g$
e/m of p = $\displaystyle 9.58\times 10^{4}: : c/g$
e/m of e = $\displaystyle 1.7588\times 10^{8}: : c/g$

Multiple choice chemistry what is inside atom neutrons discovery of neutrons structure of atoms

The triad of nuclei that is isotonic is :

  1. $^{14} _6C,\,^{15} _7N,\, ^{17} _9F$
  2. $^{12} _6C,\,^{14} _7N,\, ^{19} _9F$
  3. $^{14} _6C,\,^{14} _7N,\, ^{17} _9F$
  4. $^{14} _6C,\,^{14} _7N,\, ^{19} _9F$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The triad of nuclei that is isotonic is  $^{14} _6C,\,^{15} _7N,\, ^{17} _9F$.
Number of neutrons are
$C -14-6=8$
$N-15-7=8$
$F-17-9=8$

Multiple choice chemistry what is inside atom neutrons discovery of neutrons structure of atoms

Density of neutron is of the order of :

  1. $10^3 kg/cc$
  2. $10^6 kg/cc$
  3. $10^{12} kg/cc$
  4. $10^2 kg/cc$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

$Atomic\quad radius\quad of\quad neutron\quad =\quad { 10 }^{ -13 }cm\ mass\quad of\quad neutron\quad =\quad 1.6749\times { 10 }^{ -27 }kg\ density\quad of\quad neutron\quad =\quad \dfrac { Mass }{ Volume } =\quad { 10 }^{ 12 }\quad kg/cc$

Multiple choice chemistry structure of the atom neutrons discovery of neutrons structure of atoms

Which of the following particle has mass closest to the mass of a proton?

  1. Neutron

  2. Hydrogen molecule

  3. Alpha particle

  4. Positron

  5. Electron
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Neutron has closest mass to a proton. The mass of proton and neutron are 1.0073 amu and 1.0087 amu respectively. Mass of electron is much lower than that of proton and neutron

Multiple choice chemistry structure of the atom neutrons discovery of neutrons structure of atoms

Statement 1: Neutrons and protons are classified as nucleons.
Statement 2: Neutrons and protons are both located in the principal energy levels of the atom.

  1. <p>Both Statement 1 and Statement 2 are correct and Statement 2 is the correct explanation of Statement 1.</p>

  2. <p>Both Statement 1 and Statement 2 are correct and Statement 2 is not the correct explanation of Statement 1.</p>

  3. <p>Statement 1 is correct but Statement 2 is not correct.</p>

  4. <p>Statement 1 is not correct but Statement 2 is correct.</p>

  5. <p>Both the Statement 1 and Statement 2 are not correct. </p>
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
A nucleon is a collective name for two important subatomic particles: neutrons and protons. A nucleon is one of either of the two types of subatomic particles (neutrons and protons) which are located in the nucleus of atoms.
electrons are located in the principal energy levels of the atoms so statement 2 is not correct because neutron and proton stay in the nucleus of an atom.
Multiple choice chemistry what is inside atom neutrons discovery of neutrons structure of atoms

The ratio of neutrons in ${O}^{16}$ and ${O}^{18}$ is

  1. $8 : 10$
  2. $4 : 5$
  3. $9 : 8$
  4. $1 : 1$
Reveal answer Fill a bubble to check yourself
A,B Correct answer
Explanation

 The ratio of neutrons in $\displaystyle {O}^{16}$ and $\displaystyle {O}^{18}$ is $\displaystyle 4 : 5 \text { or } 8 : 10$
Number of neutrons in $\displaystyle {O}^{16} = 16-8=8$
Number of neutrons in $\displaystyle {O}^{18}=18-8=10$

Multiple choice chemistry structure of the atom neutrons discovery of neutrons structure of atoms

The discovery of neutron came very late because:

  1. it is present in nucleus

  2. it is a fundamental particle

  3. it does not move

  4. it does not carry any charge
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The discovery of neutron came very late because it does not carry any charge.

Neutron was discovered by Chadwick.


To overcome the failure of proton-electron hypothesis, Rutherford, in 1920, proposed the existence of neutral particle made from a close combination of proton and electron. He named it a neutron.

In 1932, Lord Chadwick proved the existence of neutron by bombarding lighter elements (boron and beryllium) with alpha particles which resulted in the emission of highly penetrating neutral radiation.

Hence, the correct option is $\text{D}$.