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Multiple choice nuclear reactions nuclear structure nuclei atomic nuclei physics

The mass defect of a certain nucleus is found to be $0.03$ amu. Its binding energy is:

  1. $27.93$ eV

  2. $27.93$ keV

  3. $27.93$ MeV

  4. $27.93$ GeV
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Mass defect  $\Delta M = 0.03$ amu
Binding energy  $E _{B} = \Delta Mc^2 = \Delta M\times 931.5 $  MeV
$\therefore \ E _{B} = 0.03\times 931.5$ MeV $ =27.93 $ MeV

Multiple choice nuclear reactions nuclear structure nuclei atomic nuclei physics

Consider the following statements
(i)All isotopes of an element have the same number of neutrons
(ii)Only one isotope of an element can be stable and non -radioactive
(iii)All elements have isotopes  
(iv)All isotopes of Carbon can form chemical compounds with Oxygen -16
The correct option regarding an isotope is 

  1. (iii) and (iv) only

  2. (ii),(iii) and (iii) only

  3. (i),(ii) and (iii) only

  4. (i),(iii) and (iv) only
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A

Isotopes are atoms of the same element having the same numbers of protons and different numbers of neutrons. All elements have isotope. Also all isotope of carbon can form chemical compounds with oxygen - 16.

Multiple choice nuclear reactions nuclear structure nuclei atomic nuclei physics

Higher the mass defect, higher will be the stability of the nucleus.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Amount of energy required to break the nucleus is known as binding energy of the nucleus.
It depends upon mass defect.
Greater  the mass defect, greater will be the binding energy
Stable nuclei have high binding energies
Multiple choice nuclear reactions nuclear structure nuclei atomic nuclei physics

1 u is equivalent to an energy of

  1. 9.315 MeV

  2. 931.5 KeV

  3. 93.15 MeV

  4. 931.5 MeV
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
According to Einstein mass energy equivalence is represented by
$E=m{ c }^{ 2 }$
Taking $m=1a.m.u$
$=1.66\times { 10 }^{ -27 }㎏$
and $c=3\times { 10 }^{ 8 }㎧$
We get, $E=1.66\times { 10 }^{ -27 }\times { \left( 3\times { 10 }^{ 8 } \right)  }^{ 2 }J$
$=1.49\times { 10 }^{ -10 }J$
As $1MeV=1.6\times { 10 }^{ -13 }J$
$\therefore E=\cfrac { 1.49\times { 10 }^{ -10 } }{ 1.6\times { 10 }^{ -13 } } $
$E=931.25MeV$
Hence,$1a.m.u.=931.25MeV$
Multiple choice nuclear reactions nuclear structure nuclei atomic nuclei physics

The mass equivalent of 931.5 MeV energy is

  1. $1.66 \times 10^{-27} kg $

  2. $6.02 \times 10^{-24}kg$

  3. $1.66 \times 10^{-20} kg$

  4. $6.02 \times 10^{-27} kg$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
According to Einstein, mass energy equivalence is represented by
$E=m{ C }^{ 2 }$
Taking $m=1a.m.u$
$=1.66\times { 10 }^{ -27 }㎏$
and $C=3\times { 10 }^{ 8 }㎧$
We get $E=1.66\times { 10 }^{ -27 }\times { (3\times { 10 }^{ 8 }) }^{ 2 }J$
$=1.49\times { 10 }^{ -10 }J$
As $1MeV=1.6\times { 10 }^{ -13 }J$
$\therefore E=\cfrac { 1.49\times { 10 }^{ -10 } }{ 1.6\times { 10 }^{ -13 } } $
$E=931.25MeV$
Hence the mass equivalent of $931.25MeV$ energy is $1.66\times { 10 }^{ -27 }㎏$
Multiple choice nuclear reactions nuclear structure nuclei atomic nuclei physics

If mass-energy equvalence is taken into account, when water is cooled to form ice, the mass of ater should

  1. Increase

  2. Remain unchanged

  3. decrease

  4. First increase and then decrease
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

As we know that when water is converted into ice then it releases 

energy to the atmosphere, in other words, it can be said that
 it releases some mass to the atmosphere because mass and 
energy are equivalent. 
So option C is correct that mass will decrease.

Multiple choice nuclear reactions nuclear structure nuclei atomic nuclei physics

Two light nuclei of masses $m _1$ and $m _2 $ are fused to form a more stable nucleus of mass $m _3$ then :-

  1. $m _3 = | m _1 - m _2 | $

  2. $m _3 < ( m _1 + m _2 ) $

  3. $m _3 > ( m _1 - m _2 ) $

  4. $m _3 = | m _1 + m _2 | $
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

When two nuclei of masses ${m _1}$ and ${m _2}$ are fused to form a stable nucleus of mass ${m _3}$ and some of the mass is converted in energy.

Therefore,

${m _3} < {m _1} + {m _2}$

Multiple choice nuclear reactions nuclear structure nuclei atomic nuclei physics

A photon of $1.7 \times 10 ^{-13}$ joule is absorbed by a material under special circumstances. The correct statement is :

  1. Electron of the atoms of absorbed material will go the higher energy states.

  2. Electron and positron pair will be created

  3. Only positron pair will be produced

  4. Photoelectric effect will occur and electron will be produced
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

For electron and positron pair production, minimum energy is $1.02\ MeV$.
Energy of photon is given: $ 1.7 \times 10^{-3} J=\dfrac{1.7 \times 10^{-13}}{1.6 \times 10^{-19}}$$=1.06 \, MeV$.
Since energy of photon is greater than 1.02 MeV, electron positron pair will be created.

Multiple choice principal and molar specific heats of gases isothermal and adiabatic processes specific heat capacity heat and thermodynamics physics

The amount of heat necessary to raise the temperature of $0.2 \ mol\ of\ N _2$ at constant pressure from $37^oC$ to $ 337^oC$  will be

  1. $746\ J$

  2. $1746\ J$

  3. $2746\ cal$

  4. $3746\ J$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

$N _2$ is a diatomic molecule thus its degree of freedom is 5. Its $C _p$ is given as $(1+\displaystyle\dfrac{f}{2})R=(1+\dfrac{5}{2})R=\dfrac{7}{2}R$
Thus, we get the heat required as $Q=nC _p\Delta T=0.2\times \displaystyle\dfrac{7}{2}\times 8.314\times 300=1746  J$