Find the energy released when two H 2 1 nuclei fuse together to form a single He 4 2 nucleus. Given, the binding energy per nucleon of H 2 1 and He 4 2 are 1 . 1 MeV and 7 . 0 MeV respectively.

In the given question we have to use the concept of Nuclear fusion and apply it to solve the given question. H 2 1 + H 2 1 → H 2 e 4 + Δ E The binding energy per nucleon of a deuteron =1.1MeV &there4; Total binding energy = 2 × 1 . 1 = 2 . 2 M e V The binding energy per nucleon of a helium nucleus =7MeV &there4; Total binding energy = 4 × 7 = 28 M e V &there4; Hence, energy released Δ E = ( 28 − 2 × 2 . 2 ) = 23 . 6 M e V . Hence, 23.6 MeV will be the correct answer.

State the difference between nuclear fission and nuclear fusion. Find the released energy Q in the given fission process: U 235 92 + n 1 0 → Xe 140 54 + Sr 38 94 + 2 n 1 0 + Q Given: mass of U 235 92 = 235 . 0439 amu mass of Xe 140 54 = 139 . 9054 amu mass of Sr 94 38 = 93 . 9063 amu mass of n 1 0 = 1 . 00867 amu 1 amu = 932 MeV

Nuclear fission is a process of splitting of a heavier nucleus into two lighter nuclei. It generally occurs in elements of high atomic mass. Nuclear fusion is a process of combination of two light nuclei to form a heavier nuclei. It generally occurs in elements of low atomic mass. In both the processes, the total mass of the products is slightly less than the mass of the original nuclei. This difference in mass is converted to energy. Energy = mass of reactant - mass of product × 931 MeV = 235 . 0439 + 1 . 00867 - 139 . 9054 + 93 . 9063 + 3 × 1 . 00867 × 931 MeV = 236 . 05268 - 235 . 8295 × 931 MeV = 0 . 22318 × 931 MeV Energy = 207 . 89217 MeV

Consider the items listed in column I and II below: Column I Column II (i) Breeder reactor (a) Fusion reactors (ii) Energy of a star (b) Controlled chain reaction (iii) Thermal neutrons (c) Fast neutrons (iv) Plasma confinement (d) Thermonuclear fusion The most appropriate matching of items in the two columns is given by

(i) - (b), (ii) - (c), (iii) - (d), (iv) - (a)

(i) - (c), (ii) - (d), (iii) - (b), (iv) - (a)

(i) - (c), (ii) - (b), (iii) - (d), (iv) - (a)

(i) - (d), (ii) - (c), (iii) - (b), (iv) - (a)

HARD

Earn 100

Write the proton-proton cycle of the source of energy in the Sun and the stars.

Important Questions on Nuclei

EASY

Physics>Modern Physics>Nuclei>Nuclear Energy

What is the nuclear fusion process ? Give an example of nuclear fusion in nature.

A star converts four helium nuclei into one oxygen nucleus. If masses of helium and oxygen nuclei are $4.0015$ amu and $15.995$ amu respectively , then find the energy released per oxygen nucleus.

HARD

Physics>Modern Physics>Nuclei>Nuclear Energy

Explain the source of energy with the help of proton proton cycle. What is the role of cadmium rod in nuclear reactor?

MEDIUM

Physics>Modern Physics>Nuclei>Nuclear Energy

Explain the supernova stage of a star. Mention the main feature of a black hole.

HARD

Physics>Modern Physics>Nuclei>Nuclear Energy

Write the equation of proton-proton cycle in the sun.

EASY

Physics>Modern Physics>Nuclei>Nuclear Energy

What is meant by pair production and annihilation?

MEDIUM

Physics>Modern Physics>Nuclei>Nuclear Energy

Distinguish between nuclear fission and nuclear fusion.

MEDIUM

Physics>Modern Physics>Nuclei>Nuclear Energy

Explain the red giant stage of a star. Which is the factor that decides the next stage of a star after its red giant stage?

MEDIUM

Physics>Modern Physics>Nuclei>Nuclear Energy

The ratio of the energy released by

4 kg

of hydrogen at sun by fusion process to

23.5 kg

{}^{235}U

in the nuclear reactor by fission process is (Assume energy released per fusion is

26 MeV

and that per fission is

200 MeV

)

HARD

Physics>Modern Physics>Nuclei>Nuclear Energy

Find the energy released when two ${}_{1}{H^{2}}$ nuclei fuse together to form a single ${}_{2}{He}^{4}$ nucleus. Given, the binding energy per nucleon of ${}_{1}{H^{2}}$ and ${}_{2}{He}^{4}$ are $1.1 MeV$ and $7.0 MeV$ respectively.

HARD

Physics>Modern Physics>Nuclei>Nuclear Energy

Write down different set of proton-proton cycle of fusion reaction in the sun.

MEDIUM

Physics>Modern Physics>Nuclei>Nuclear Energy

What kind of nuclear reaction is the source of the sun's energy?

MEDIUM

Physics>Modern Physics>Nuclei>Nuclear Energy

An electron, a doubly ionized helium ion

({He}^{+ +})

and proton are having the same kinetic energy. The relation between their respective de-Broglie wavelength

λ_{e}, λ_{{He}^{+ +}}

and

λ_{p}

is :

MEDIUM

Physics>Modern Physics>Nuclei>Nuclear Energy

A nuclear fuel rod generates energy at a rate of

5 \times 10^{8} W m^{- 3} .

It is in the shape of a cylinder of radius

4.0 mm

and length

0.20 m .

A coolant of specific heat

4 \times 10^{3} J {kg}^{- 1} K^{- 1}

flows, past it at a rate of,

0.2 kg s^{- 1}

. The temperature rise in this coolant is approximately,

MEDIUM

Physics>Modern Physics>Nuclei>Nuclear Energy

State the difference between nuclear fission and nuclear fusion. Find the released energy $Q$ in the given fission process:

${}_{92}{U^{235}} + {}_{0}{n^{1}} \to {}_{54}{Xe}^{140} + {}_{38}{Sr}^{94} + 2 {}_{0}{n^{1}} + Q$

Given:

mass of ${}_{92}{U^{235}} = 235.0439 amu$

mass of ${}_{54}{Xe}^{140} = 139.9054 amu$

mass of ${}_{38}{Sr}^{94} = 93.9063 amu$

mass of ${}_{0}{n^{1}} = 1.00867 amu$

$1 amu = 932 MeV$

MEDIUM

Physics>Modern Physics>Nuclei>Nuclear Energy

2 M e V

neutron is emitted in a fission reactor. If it looses half of its kinetic energy in each collision with a moderator atom, how many collisions must it undergo to achieve thermal energy of

0.039 e V

HARD

Physics>Modern Physics>Nuclei>Nuclear Energy

In a reactor,

2 kg

{}_{92}U^{235}

fuel is fully used up in

30

days. The energy released fission is

200 MeV

. Given that the Avogadro number,

N = 6.023 \times 10^{26}

per kilo mole and

1 eV = 1.6 \times 10^{- 19} J

. The power output of the reactor is close to:

MEDIUM

Physics>Modern Physics>Nuclei>Nuclear Energy

A nucleus, initially at rest, breaks up into two nuclear fragments with their radii in the ratio

2 : 1 .

Then their velocities will be in the ratio

EASY

Physics>Modern Physics>Nuclei>Nuclear Energy

Write one balanced equation of Nuclear fusion.

MEDIUM

Physics>Modern Physics>Nuclei>Nuclear Energy

Consider the items listed in column I and II below:

Column I	Column II
(i) Breeder reactor	(a) Fusion reactors
(ii) Energy of a star	(b) Controlled chain reaction
(iii) Thermal neutrons	(c) Fast neutrons
(iv) Plasma confinement	(d) Thermonuclear fusion

The most appropriate matching of items in the two columns is given by

MEDIUM

Physics>Modern Physics>Nuclei>Nuclear Energy

The Binding energy per nucleon of

{}_{3}^{7}{L i}

and

{}_{2}^{4}{H e}

nucleon are

5.60 M e V

and

7.06 M eV

, respectively. In the nuclear reaction

_{3}^{7} L i +_{1}^{1} H \to_{2}^{4} H e +_{2}^{4} H e + Q

, the value of energy

Q

released is

Write the proton-proton cycle of the source of energy in the Sun and the stars.

Important Questions on Nuclei

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