Nuclear Physics | Physics JEE previous year questions with Solutions

Q 1 :

Binding energy of a certain nucleus is $18 \times 10^{8}$ J. How much is the difference between total mass of all the nucleons and nuclear mass of the given nucleus [2024]

$0.2$ $μ g$
$20$ $μ g$
$10$ $μ g$
$2$ $μ g$

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(2)

$Δ m c^{2} = 18 \times 10^{8}$

$Δ m \times 9 \times 10^{16} = 18 \times 10^{8}$

$Δ m = 2 \times 10^{- 8} kg = 20 μ g$

Q 2 :

If $M_{o}$ is the mass of isotope ${}_{5}^{12}B$ , $M_{p}$ and $M_{n}$ are the masses of proton and neutron, then nuclear binding energy of isotope is [2024]

$(M_{o} - 5 M_{p} - 7 M_{n}) C^{2}$
$(M_{o} - 12 M_{n}) C^{2}$
$(M_{o} - 5 M_{p}) C^{2}$
$(5 M_{p} + 7 M_{n} - M_{o}) C^{2}$

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(4)

${}_{5}^{12}B ⟶ 5 p r o t o n + 7 n e u t r o n$

$B . E = Δ m c^{2}$

$(5 M_{p} + 7 M_{n} - M_{o}) c^{2}$

Q 3 :

The energy equivalent of 1 g of substance is: [2024]

$11.2 \times 10^{24} M e V$
$5.6 \times 10^{12} M e V$
$5.6 e V$
$5.6 \times 10^{26} M e V$

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(4)

$E = 10^{- 3} \times 9 \times 10^{16} J (∵ E = M c^{2})$

$E = 9 \times 10^{- 13} J$

$1 J = \frac{1}{1.6 \times 10^{- 19}} e V$

$E = 9 \times 10^{13} \times \frac{1}{1.6 \times 10^{- 19}} eV = 5.6 \times 10^{26} MeV$

Q 4 :

The atomic mass of ${}_{6}C^{12}$ is 12.00000u and that of ${}_{6}C^{13}$ is 13.003354u. The required energy to remove a neutron from ${}_{6}C^{13}$ , if mass of neutron is 1.008665u, will be [2024]

62.5 MeV
6.25 MeV
4.95 MeV
49.5 MeV

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(3)

${}_{6}C^{13} + Energy \to {}_{6}C^{12} + {}_{0}n^{1}$

$Δ m = 12 + 1.008665 - 13.003354$

$= - 0.00531 u$

$∴ Energy required = 0.00531 \times 931.5 MeV$

$= 4.95 MeV$

Q 5 :

If three helium nuclei combine to form a carbon nucleus then the energy released in this reaction is _________ $\times 10^{- 2}$ MeV. (Given 1u = 931 MeV/ $c^{2}$ , atomic mass of helium = 4.002603u). [2024]

(727) Reaction: $3 {}_{2}^{4}H e \to_{6}^{12} C + Q$

Energy released

$Q = [3 M_{He} - M_{C}] c^{2} = [3 \times 4.002603 - 12] [931]$

$Q = 727 \times 10^{- 2} MeV$

Q 6 :

A star has 100% helium composition. It starts to convert three ${}^{4}H e$ into one ${}^{12}C$ via triple alpha process as ${}^{4}H e + {}^{4}H e + {}^{4}H e \to {}^{12}C + Q$ . The mass of the star is $2.0 \times 10^{32}$ kg and it generates energy at the rate of $5.808 \times 10^{30}$ W. The rate of converting these ${}^{4}H e$ is $n \times 10^{42}$ $s^{- 1}$ , where $n$ is _______ .

[Take, mass of ${}^{4}H e$ = 4.0026 u, mass of ${}^{12}C$ = 12 u] [2024]

(5) ${}_{2}^{4}H e + {}_{2}^{4}H e + {}_{2}^{4}H e \to {}_{6}^{12}C + Q \Rightarrow 3 {}_{2}^{4}H e \to {}_{6}^{12}C + Q$

$Q = (3 m_{{}^{4}H e} - m_{{}^{12}C}) c^{2}$

$Q = (3 \times 4.0026 - 12) {(3 \times 10^{8})}^{2} = 7.266 MeV$

Power generated $P = \frac{N}{t} Q$ (N = No. of reactions/sec)

$\frac{N}{t} = \frac{P}{Q} = \frac{5.808 \times 10^{30}}{7.266 \times 10^{6} \times 1.6 \times 10^{- 19}} = 5 \times 10^{42}$

Rate of conversion of ${}^{4}H e$ in ${}^{12}C = 5 \times 10^{42}$

Q 7 :

In a nuclear fission process, a high mass nuclide (A $\approx$ 236) with binding energy 7.6 MeV/Nucleon dissociated into middle mass nuclides (A $\approx$ 118), having binding energy of 8.6 MeV/Nucleon. The energy released in the process would be _______ meV. [2024]

(236) $Q = B E_{Product} - B E_{Reactant}$

$= 2 (118) (8.6) - 236 (7.6) = 236 \times 1 = 236 MeV$

Q 8 :

The mass defect in a particular reaction is 0.4 g. The amount of energy liberated is $n \times 10^{7}$ kWh, where n = ______. (speed of light = $3 \times 10^{8}$ m/s) [2024]

(1) $E = Δ m c^{2}$

$= 0.4 \times 10^{- 3} \times {(3 \times 10^{8})}^{2} = 3600 \times 10^{7} kWs$

$= \frac{3600 \times 10^{7}}{3600} kWh = 1 \times 10^{7} kWh$

Q 9 :

In a nuclear fission reaction of an isotope of mass M three similar daughter nuclei of same mass are formed. The speed of a daughter nuclei in terms of mass defect $∆ M$ will be [2024]

$\sqrt{\frac{2 c Δ M}{M}}$
$\frac{Δ M c^{2}}{3}$
$c \sqrt{\frac{2 Δ M}{M}}$
$c \sqrt{\frac{3 Δ M}{M}}$

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(3)

$M = 3 m$

$Δ K . E . = energy released due to fission$

$3 (\frac{1}{2} m v^{2}) = Δ M C^{2}$

$\frac{3}{2} m v^{2} = Δ M C^{2}$

$v^{2} = \frac{2 Δ M C^{2}}{M}$

$v = \sqrt{\frac{2 Δ M C^{2}}{M}} = C \sqrt{\frac{2 Δ M}{M}}$

Q 10 :

Given below are two statements. One is labelled as Assertion (A) and the other is labelled as Reason (R). [2025]

Assertion (A): The binding energy per nucleon is found to be practically independent of the atomic number A, for nuclei with mass numbers between 30 and 170.

Reason (R): Nuclear force is long range.

In the light of the above statements, choose the correct answer from the options given below:

(A) is false but (R) is true
(A) is true but (R) is false
Both (A) and (R) are true and (R) is the correct explanation of (A)
Both (A) and (R) are true but (R) is NOT the correct explanation of (A)

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(2)

From graph between B.E/N and A we can see BE/N is almost constant ⇒ correct

Reason ⇒ incorrect as nuclear forces are short range forces.

Q 11 :

Energy released when two deuterons $({}_{1}{H^{2}})$ fuse to form a helium nucleus $({}_{2}{He}^{4})$ is:

(Given: Binding energy per nucleon of ${}_{1}{H^{2}} = 1.1 MeV$ and binding energy per nucleon of ${}_{2}{He}^{4} = 7.0 MeV$ ) [2025]

8.1 MeV
5.9 MeV
23.6 MeV
26.8 MeV

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(3)

${}_{1}{H^{2} + {}_{1}{H^{2}} \to {}_{2}{He}^{4}}$

$Q = B E_{Product} - B E_{Reactant}$

$Q = (4 \times 7 - 4 \times 1.1) MeV = 23.6 MeV$

Q 12 :

The mass of proton, neutron and helium nucleus are respectively 1.0073 u, 1.0087 u and 4.0015 u. The binding energy of helium nucleus is [2023]

14.2 MeV
28.4 MeV
56.8 MeV
7.1 MeV

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(2)

$B . E . of Helium = (2 m_{p} + 2 m_{N} - m_{He}) c^{2} = 28.4 MeV$

Q 13 :

${}_{92}^{238}A \to {}_{90}^{234}B + {}_{2}^{4}D + Q$

In the given nuclear reaction, the approximate amount of energy released will be: [2023]

[Given, mass of ${}_{92}^{238}A = 238.05079 \times 931.5 MeV / c^{2}$

mass of ${}_{90}^{234}B = 234.04363 \times 931.5 MeV / c^{2}$

mass of ${}_{2}^{4}D = 4.00260 \times 931.5 MeV / c^{2}$ ]

3.82 MeV
5.9 MeV
2.12 MeV
4.25 MeV

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(4)

$Q = (m_{A} - m_{B} - m_{D}) \times 931.5 MeV$

$= (238.05079 - 234.04363 - 4.00260) \times 931.5$

$\Rightarrow 4.25 MeV$

Q 14 :

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R [2023]

Assertion A: The binding energy per nucleon is practically independent of the atomic number for nuclei of mass number in the range 30 to 170.

Reason R: Nuclear force is short ranged.

In the light of the above statements, choose the correct answer from the options given below:

Both A and R are true but R is NOT the correct explanation of A
A is true but R is false
A is false but R is true
Both A and R are true and R is the correct explanation of A

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(4)

Binding energy per nucleon is almost same for nuclei of mass number ranging 30 to 170.

Q 15 :

Nucleus A having Z = 17 and equal number of protons and neutrons has 1.2 MeV binding energy per nucleon. Another nucleus B of Z = 12 has total 26 nucleons and 1.8 MeV binding energy per nucleon. The difference of binding energy of B and A will be ______ MeV. [2023]

(6)

$For A mass number = 34$

$Total binding energy = 1.2 \times 34 = 40.8 MeV$

$For B mass number = 26$

$Total binding energy = 1.8 \times 26 MeV = 46.8 MeV$

$Difference of BE = 6 MeV$

Q 16 :

If the binding energy of ground state electron in a hydrogen atom is $13.6 eV$ , then, the energy required to remove the electron from the second excited state of ${Li}^{2 +}$ will be: $x \times 10^{- 1} eV$ . The value of $x$ is _______ . [2023]

(136)

$E_{H} = 13.6$

$E_{Li}^{2} = 13.6 \frac{Z^{2}}{n^{2}} = 13.6 \times \frac{9}{9} = 13.6 eV = 136 \times 10^{- 1} eV$

Q 17 :

A nucleus with mass number 242 and binding energy per nucleon as 7.6 MeV breaks into two fragment each with mass number 121. If each fragment nucleus has binding energy per nucleon as 8.1 MeV, the total gain in binding energy is ________ MeV. [2023]

(121)

$Initial binding energy = 242 \times 7.6 MeV$

$Final binding energy = 121 \times 8.1 MeV + 121 \times 8.1 MeV = 242 \times 8.1 MeV$

$Total gain in binding energy = 242 (8.1 - 7.6) = 121 MeV$

Q 18 :

A common example of alpha decay is

   ${}_{92}^{238}U \to {}_{90}^{234}{Th} + {}_{2}{He}^{4} + Q$

Given:   ${}_{92}^{238}U = 238.05060 u$

   ${}_{90}^{234}{Th} = 234.04360 u$

   ${}_{2}^{4}{He} = 4.00260 u and 1 u = 931.5 \frac{MeV}{e^{2}}$

The energy released $(Q)$ during the alpha decay of ${}_{92}^{238}U$ is ________ MeV. [2023]

(4)

$Energy released = {(Δ m)}_{amu} \times 931.5 MeV$

$= {(m_{u} - m_{Th} - m_{He})}_{amu} \times 931.5 MeV$

$= 0.0044 \times 931.5 MeV = 4.0986 MeV$

Q 19 :

Given below are two statements:

Statement I: For all elements, greater the mass of the nucleus, greater is the binding energy per nucleon.

Statement II: For all elements, nuclei with less binding energy per nucleon transform to nuclei with greater binding energy per nucleon.

In the light of the above statements, choose the correct answer from the options given below: [2026]

Statement I is true but Statement II is false
Both Statement I and Statement II are false
Statement I is false but Statement II is true
Both Statement I and Statement II are true

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(3)

Theoretical

Q 20 :

The minimum frequency of photon required to break a particle of mass 15.348 amu into 4 $α$ particles is _______ kHz.

[Mass of He nucleus = 4.002 amu, 1 amu = $1.66 \times 10^{- 27}$ kg, $h = 6.6 \times 10^{- 34}$ J.s and $c = 3 \times 10^{8}$ m/s] [2026]

$14.94 \times 10^{19}$
$9 \times 10^{19}$
$9 \times 10^{20}$
$14.94 \times 10^{20}$

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(1)

$h ν = (4 \times 4.002 - 15.348) \times 1.66 \times 10^{- 27} \times {(3 \times 10^{8})}^{2}$

$ν = 14.94 \times 10^{19} kHz$

Q 21 :

The binding energy for the following nuclear reactions are expressed in MeV.

${}_{2}{He}^{3} + {{}_{0}n}^{1} \to {}_{2}{He}^{4} + 20 MeV$

${}_{2}{He}^{4} + {{}_{0}n}^{1} \to {}_{2}{He}^{5} - 0.9 MeV$

If $X_{3}, X_{4}, X_{5}$ denote the stability of ${}_{2}{He}^{3}, {}_{2}{He}^{4}$ and ${}_{2}{He}^{5}$ respectively, then the correct order is: [2026]

$X_{4} > X_{5} > X_{3}$
$X_{4} < X_{5} < X_{3}$
$X_{4} > X_{5} < X_{3}$
$X_{4} = X_{5} = X_{3}$

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(1)

${BE}_{{He}^{4}} - {BE}_{{He}^{3}} = 20 MeV \dots (1)$

${BE}_{{He}^{5}} - {BE}_{{He}^{4}} = - 0.9 MeV \dots (2)$

$From eq (1) & (2)$

${BE}_{{He}^{4}} > {BE}_{{He}^{5}} > {BE}_{{He}^{3}}$

$X_{4} > X_{5} > X_{3}$

Q 22 :

The average energy released per fission for the nucleus of ${}_{92}^{235}U$ is 190 MeV. When all the atoms of 47 g pure ${}_{92}^{235}U$ undergo fission process, the energy released is $α \times 10^{23} MeV$ . The value of $α$ is ______.

(Avogadro Number $= 6 \times 10^{23}$ per mole) [2026]

(228)

$Total number of U-235 atoms is$

$47 g = \frac{47}{235} moles = \frac{1}{5} moles$

$∴$ $Total energy released = \frac{1}{5} \times 6 \times 10^{23} \times 190 MeV$

$= 228 \times 10^{23} MeV$

Topic Question Set

Q 1 :

Binding energy of a certain nucleus is $18 \times 10^{8}$ J. How much is the difference between total mass of all the nucleons and nuclear mass of the given nucleus [2024]

Q 2 :

If $M_{o}$ is the mass of isotope ${}_{5}^{12}B$ , $M_{p}$ and $M_{n}$ are the masses of proton and neutron, then nuclear binding energy of isotope is [2024]

Q 3 :

The energy equivalent of 1 g of substance is: [2024]

Q 4 :

The atomic mass of ${}_{6}C^{12}$ is 12.00000u and that of ${}_{6}C^{13}$ is 13.003354u. The required energy to remove a neutron from ${}_{6}C^{13}$ , if mass of neutron is 1.008665u, will be [2024]

Q 5 :

If three helium nuclei combine to form a carbon nucleus then the energy released in this reaction is _________ $\times 10^{- 2}$ MeV. (Given 1u = 931 MeV/ $c^{2}$ , atomic mass of helium = 4.002603u). [2024]

Q 7 :

In a nuclear fission process, a high mass nuclide (A $\approx$ 236) with binding energy 7.6 MeV/Nucleon dissociated into middle mass nuclides (A $\approx$ 118), having binding energy of 8.6 MeV/Nucleon. The energy released in the process would be _______ meV. [2024]

Q 8 :

The mass defect in a particular reaction is 0.4 g. The amount of energy liberated is $n \times 10^{7}$ kWh, where n = ______. (speed of light = $3 \times 10^{8}$ m/s) [2024]

Q 9 :

In a nuclear fission reaction of an isotope of mass M three similar daughter nuclei of same mass are formed. The speed of a daughter nuclei in terms of mass defect $∆ M$ will be [2024]

Q 11 :

Energy released when two deuterons $({}_{1}{H^{2}})$ fuse to form a helium nucleus $({}_{2}{He}^{4})$ is:

(Given: Binding energy per nucleon of ${}_{1}{H^{2}} = 1.1 MeV$ and binding energy per nucleon of ${}_{2}{He}^{4} = 7.0 MeV$ ) [2025]

Q 12 :

The mass of proton, neutron and helium nucleus are respectively 1.0073 u, 1.0087 u and 4.0015 u. The binding energy of helium nucleus is [2023]

Q 15 :

Nucleus A having Z = 17 and equal number of protons and neutrons has 1.2 MeV binding energy per nucleon. Another nucleus B of Z = 12 has total 26 nucleons and 1.8 MeV binding energy per nucleon. The difference of binding energy of B and A will be ______ MeV. [2023]

Q 16 :

If the binding energy of ground state electron in a hydrogen atom is $13.6 eV$ , then, the energy required to remove the electron from the second excited state of ${Li}^{2 +}$ will be: $x \times 10^{- 1} eV$ . The value of $x$ is _______ . [2023]

Q 17 :

A nucleus with mass number 242 and binding energy per nucleon as 7.6 MeV breaks into two fragment each with mass number 121. If each fragment nucleus has binding energy per nucleon as 8.1 MeV, the total gain in binding energy is ________ MeV. [2023]

Q 20 :

The minimum frequency of photon required to break a particle of mass 15.348 amu into 4 $α$ particles is _______ kHz.

[Mass of He nucleus = 4.002 amu, 1 amu = $1.66 \times 10^{- 27}$ kg, $h = 6.6 \times 10^{- 34}$ J.s and $c = 3 \times 10^{8}$ m/s] [2026]

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Topic Question Set

Q 1 : Binding energy of a certain nucleus is 18×108J. How much is the difference between total mass of all the nucleons and nuclear mass of the given nucleus [2024]

Q 2 : If Mo is the mass of isotope B512, Mp and Mn are the masses of proton and neutron, then nuclear binding energy of isotope is [2024]

Q 3 : The energy equivalent of 1 g of substance is: [2024]

Q 4 : The atomic mass of C126 is 12.00000u and that of C136 is 13.003354u. The required energy to remove a neutron from C136, if mass of neutron is 1.008665u, will be [2024]

Q 5 : If three helium nuclei combine to form a carbon nucleus then the energy released in this reaction is _________ ×10-2 MeV. (Given 1u = 931 MeV/c2, atomic mass of helium = 4.002603u). [2024]

Q 7 : In a nuclear fission process, a high mass nuclide (A ≈ 236) with binding energy 7.6 MeV/Nucleon dissociated into middle mass nuclides (A ≈ 118), having binding energy of 8.6 MeV/Nucleon. The energy released in the process would be _______ meV. [2024]

Q 8 : The mass defect in a particular reaction is 0.4 g. The amount of energy liberated is n×107 kWh, where n = ______. (speed of light = 3×108 m/s) [2024]

Q 9 : In a nuclear fission reaction of an isotope of mass M three similar daughter nuclei of same mass are formed. The speed of a daughter nuclei in terms of mass defect ∆M will be [2024]

Q 11 : Energy released when two deuterons (H21) fuse to form a helium nucleus (He42) is: (Given: Binding energy per nucleon of H21=1.1 MeV and binding energy per nucleon of He42=7.0 MeV) [2025]

Q 12 : The mass of proton, neutron and helium nucleus are respectively 1.0073 u, 1.0087 u and 4.0015 u. The binding energy of helium nucleus is [2023]

Q 13 : A92238→B90234+D24+Q In the given nuclear reaction, the approximate amount of energy released will be: [2023] [Given, mass of A92238=238.05079×931.5 MeV/c2 mass of B90234=234.04363×931.5 MeV/c2 mass of D24=4.00260×931.5 MeV/c2]

Q 15 : Nucleus A having Z = 17 and equal number of protons and neutrons has 1.2 MeV binding energy per nucleon. Another nucleus B of Z = 12 has total 26 nucleons and 1.8 MeV binding energy per nucleon. The difference of binding energy of B and A will be ______ MeV. [2023]

Q 16 : If the binding energy of ground state electron in a hydrogen atom is 13.6 eV, then, the energy required to remove the electron from the second excited state of Li2+ will be: x×10-1 eV. The value of x is _______ . [2023]

Q 17 : A nucleus with mass number 242 and binding energy per nucleon as 7.6 MeV breaks into two fragment each with mass number 121. If each fragment nucleus has binding energy per nucleon as 8.1 MeV, the total gain in binding energy is ________ MeV. [2023]

Q 18 : A common example of alpha decay is U92238→Th90234+He42+Q Given: U92238=238.05060 u Th90234=234.04360 u He24=4.00260 u and 1 u=931.5 MeVe2 The energy released (Q) during the alpha decay of U92238 is ________ MeV. [2023]

Q 20 : The minimum frequency of photon required to break a particle of mass 15.348 amu into 4 α particles is _______ kHz. [Mass of He nucleus = 4.002 amu, 1 amu = 1.66×10-27 kg, h=6.6×10-34 J.s and c=3×108 m/s] [2026]

Q 21 : The binding energy for the following nuclear reactions are expressed in MeV. He23+n01→He24+20 MeV He24+n01→He25-0.9 MeV If X3,X4,X5 denote the stability of He23,He24 and He25 respectively, then the correct order is: [2026]

Q 22 : The average energy released per fission for the nucleus of U92235 is 190 MeV. When all the atoms of 47 g pure U92235 undergo fission process, the energy released is α×1023 MeV. The value of α is ______. (Avogadro Number =6×1023 per mole) [2026]

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Q 1 :

Binding energy of a certain nucleus is $18 \times 10^{8}$ J. How much is the difference between total mass of all the nucleons and nuclear mass of the given nucleus [2024]

Q 2 :

If $M_{o}$ is the mass of isotope ${}_{5}^{12}B$ , $M_{p}$ and $M_{n}$ are the masses of proton and neutron, then nuclear binding energy of isotope is [2024]

Q 3 :

The energy equivalent of 1 g of substance is: [2024]

Q 4 :

The atomic mass of ${}_{6}C^{12}$ is 12.00000u and that of ${}_{6}C^{13}$ is 13.003354u. The required energy to remove a neutron from ${}_{6}C^{13}$ , if mass of neutron is 1.008665u, will be [2024]

Q 5 :

If three helium nuclei combine to form a carbon nucleus then the energy released in this reaction is _________ $\times 10^{- 2}$ MeV. (Given 1u = 931 MeV/ $c^{2}$ , atomic mass of helium = 4.002603u). [2024]

Q 7 :

In a nuclear fission process, a high mass nuclide (A $\approx$ 236) with binding energy 7.6 MeV/Nucleon dissociated into middle mass nuclides (A $\approx$ 118), having binding energy of 8.6 MeV/Nucleon. The energy released in the process would be _______ meV. [2024]

Q 8 :

The mass defect in a particular reaction is 0.4 g. The amount of energy liberated is $n \times 10^{7}$ kWh, where n = ______. (speed of light = $3 \times 10^{8}$ m/s) [2024]

Q 9 :

In a nuclear fission reaction of an isotope of mass M three similar daughter nuclei of same mass are formed. The speed of a daughter nuclei in terms of mass defect $∆ M$ will be [2024]

Q 11 :

Energy released when two deuterons $({}_{1}{H^{2}})$ fuse to form a helium nucleus $({}_{2}{He}^{4})$ is:

(Given: Binding energy per nucleon of ${}_{1}{H^{2}} = 1.1 MeV$ and binding energy per nucleon of ${}_{2}{He}^{4} = 7.0 MeV$ ) [2025]

Q 12 :

The mass of proton, neutron and helium nucleus are respectively 1.0073 u, 1.0087 u and 4.0015 u. The binding energy of helium nucleus is [2023]

Q 15 :

Nucleus A having Z = 17 and equal number of protons and neutrons has 1.2 MeV binding energy per nucleon. Another nucleus B of Z = 12 has total 26 nucleons and 1.8 MeV binding energy per nucleon. The difference of binding energy of B and A will be ______ MeV. [2023]

Q 16 :

If the binding energy of ground state electron in a hydrogen atom is $13.6 eV$ , then, the energy required to remove the electron from the second excited state of ${Li}^{2 +}$ will be: $x \times 10^{- 1} eV$ . The value of $x$ is _______ . [2023]

Q 17 :

A nucleus with mass number 242 and binding energy per nucleon as 7.6 MeV breaks into two fragment each with mass number 121. If each fragment nucleus has binding energy per nucleon as 8.1 MeV, the total gain in binding energy is ________ MeV. [2023]

Q 20 :

The minimum frequency of photon required to break a particle of mass 15.348 amu into 4 $α$ particles is _______ kHz.

[Mass of He nucleus = 4.002 amu, 1 amu = $1.66 \times 10^{- 27}$ kg, $h = 6.6 \times 10^{- 34}$ J.s and $c = 3 \times 10^{8}$ m/s] [2026]