Nucleus - NEET Physics Questions
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Nucleus

Practice Questions:
Question 71: easy

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).

Assertion (A): Binding energy per nucleon for atoms having mass number between \(30\) to \(170\), almost remains same.

Reason (R): Nuclear force is a short range force and hence get saturated.

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

1. Both (A) and (R) are true and (R) is the correct explanation of (A)
2. Both (A) and (R) are true but (R) is not the correct explanation of (A)
3. (A) is true but (R) is false
4. Both (A) and (R) are false
View Answer

The binding energy per nucleon is nearly constant in the range \(30 < A < 170\) due to the short-range nature and saturation property of nuclear forces. Thus, both Assertion and Reason are true and the Reason is the correct explanation.

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Question 72: easy

The correct statement regarding nuclear force is

1. It is short range and charge dependent.
2. It is long range and charge dependent.
3. It is short range and charge independent.
4. It is long range and charge independent.
View Answer

Nuclear forces are very short-range forces (acting within femtometers) and they are charge independent, meaning the force between proton-proton, neutron-neutron, and proton-neutron is approximately the same.

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Question 73: moderate

Consider the following statements:

(a) Nuclear density is directly proportional to cube root of mass number.

(b) Binding energy per nucleon is maximum for elements having mass number \(A > 170\).

(c) When two deuterium nuclei fuse together to form a tritium nucleus we get a proton.

(d) Neutrons and protons are bound in a nucleus by the short range weak nuclear force.

The correct statement(s) is/are

1. Both (a) and (b)
2. Only (b)
3. Only (c)
4. Both (c) and (d)
View Answer

Only statement (c) is correct: \(2\text{H} + 2\text{H} \rightarrow 3\text{H} + 1\text{p}\). Nuclear density is independent of mass number, and binding energy per nucleon peaks around Iron \((A=56)\).

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Question 74: moderate

A nucleus of mass number 238 at rest emits an alpha particle with kinetic energy \(5.4\text{ MeV}\). The Q value of reaction is

1. 5.49 MeV
2. 5.88 MeV
3. 5.67 MeV
4. 5.60 MeV
View Answer

The relation between Q-value and kinetic energy is \(Q = K_{\alpha} \left(1 + \frac{m_{\alpha}}{M_{\text{daughter}}}\right) = 5.4 \times \left(1 + \frac{4}{234}\right) \approx 5.49\text{ MeV}\).

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