Find nuclear mass density of U 92 238 . Given R 0 = 1 . 5 fm and mass of each nucleon = 1 . 67 × 10 - 27 kg . .

Given, R 0 = 1 . 5 fm Mass per nucleon, M = 1 . 67 × 10 - 27 kg The mass number, A = 238 Density = Mass Volume ⇒ d = A × M A × 4 3 π R 0 3 = 238 × 1.66 × 10 − 27 238 × 4 3 π × ( 1.5 × 10 − 15 ) 3 = 1 .18 × 10 17 kg / m 3

Compare the radii of the nuclei of mass numbers 27 and 64 .

Given the mas number of the nuclei : A 1 = 27 A 2 = 64 The volume of the nucleus is directly proportional to the cube root of number of nucleons ( mass number ) constituting the nucleus. R = R 0 A 1 / 3 , where R 0 is an empirical constant.and, A = mass number. Therefore, the ratio of the radii of the nuclei having mass numbers A 1 and A 2 will be R 1 R 2 = A 1 A 2 1 3 , Putting the values, we have, R 1 R 2 = 27 64 1 3 = 3 : 4

Explain the principle and working of a nuclear reactor with the help of a labelled diagram.

NUCLEAR REACTOR A nuclear reactor is a device to produce nuclear energy based on controlled nuclear chain reaction. Principle of nuclear reactor: It works on the principle of achieving controlled chain reaction of Uranium enriched with U 235 and as a result generating huge amount of energy. The chain reaction is controlled slowing down the fission neutrons to thermal neutrons by using a moderator. The reaction rate is maintained controlled rods that can absorb neutrons Working: 1. Neutron induced fission releases energy plus extra fast neutrons. 2. Fast neutrons are slowed down by a “moderator” such as water or graphite, allowing chain reaction to occur. 3. Chain reaction is controlled by controlling the condition of the moderator, or by use of neutron absorbing materials (e.g. cadmium control rods) 4. Heat is removed by some form of heat exchanger where it is used to run a heat engine.

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What are isotones and isomers?

Important Questions on Nuclei

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Physics Crash Course (Based on Revised Syllabus-2023)>Chapter 14 - Nuclei>Exercise>Q 8

What is a.m.u.? What is its equivalent energy?

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Physics Crash Course (Based on Revised Syllabus-2023)>Chapter 14 - Nuclei>Exercise>Q 9

Neutrons can not produce ionisation. Why?

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Physics Crash Course (Based on Revised Syllabus-2023)>Chapter 14 - Nuclei>Exercise>Q 10

Write a short note on discovery of neutron.

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Physics Crash Course (Based on Revised Syllabus-2023)>Chapter 14 - Nuclei>Exercise>Q 11

What are properties of a neutron?

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Physics Crash Course (Based on Revised Syllabus-2023)>Chapter 14 - Nuclei>Exercise>Q 12

A periodic table might list the average atomic mass of magnesium as being

24.312 u

, which is the result of weighing the atomic masses of magnesium isotopes according to their natural abundances on Earth. The three isotopes and their masses are

{Mg}^{24} (23.985 04 u)

{Mg}^{25} (24.985 84 u)

and

{Mg}^{26} (25.982 59 u)

. The natural abundance of

{Mg}^{24}

78.99 %

by mass (that is

78.99 %

of the mass of a naturally occurring sample of magnesium is due to the presence of

{Mg}^{24}

). What is the abundance of (a)

{Mg}^{25}

and (b)

{Mg}^{26}

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Physics Crash Course (Based on Revised Syllabus-2023)>Chapter 14 - Nuclei>Exercise>Q 13

The strong neutron excess (defined as

N - Z

) of a high-mass nuclei, illustrated by noting that most high-mass nuclides could never fission into two stable nuclei without neutrons being left over. For example, consider the spontaneous fission of a

U^{235}

nucleus into two stable daughter nuclei with atomic numbers

39

and

53

. Determine the name of the (a) first and (b) second daughter nucleus. From the figure, approximately how many neutrons are in the (c) first and (d) second? (e) Approximately how many neutrons are left over?

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Physics Crash Course (Based on Revised Syllabus-2023)>Chapter 14 - Nuclei>Exercise>Q 14

The nuclear radius of

{}_{8}^{16}O

3 \times 10^{- 15} m .

Find the density of nuclear matter. Take, the mass of proton and neutron to be,

m = 1.67 \times 10^{- 27} kg

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Physics Crash Course (Based on Revised Syllabus-2023)>Chapter 14 - Nuclei>Exercise>Q 15

Find nuclear mass density of

{}_{92}^{238}U

. Given

R_{0} = 1.5 fm

and mass of each nucleon

= 1.67 \times 10^{- 27} kg .

What are isotones and isomers?

Important Questions on Nuclei

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