Atoms And Nuclei Chapter-Wise Test 1

Correct answer Carries: 4.

Wrong Answer Carries: -1.

What is the primary factor limiting the size of stable nuclei?

In large nuclei, the Coulomb repulsion between protons increases with atomic number, counteracting the nuclear force and reducing stability, limiting the size of stable nuclei.

Nuclear density
Mass defect
Coulomb repulsion
Binding energy decrease
3

How much energy is equivalent to a mass defect of \( 0.1 \, \text{u} \)? (Given \( 1 \, \text{u} = 931.5 \, \text{MeV/c}^2 \))

Energy = \( \Delta M \cdot c^2 \).

\( \Delta M = 0.1 \, \text{u} \).

Energy = \( 0.1 \times 931.5 = 93.15 \, \text{MeV} \).

93.15 MeV
9.315 MeV
931.5 MeV
46.58 MeV
1

The binding energy per nucleon of a nucleus is \( 8.5 \, \text{MeV} \). What is the total binding energy for a nucleus with mass number 20?

Total binding energy = \( E_{bn} \times A \).

\( E_{bn} = 8.5 \, \text{MeV} \), \( A = 20 \).

\( E_b = 8.5 \times 20 = 170 \, \text{MeV} \).

160 MeV
170 MeV
180 MeV
190 MeV
2

What is the primary source of energy in stars like the Sun?

The energy in stars like the Sun is generated through nuclear fusion, where light nuclei (e.g., hydrogen) combine to form heavier nuclei (e.g., helium), releasing energy due to increased binding energy per nucleon.

Nuclear fusion
Nuclear fission
Chemical combustion
Gravitational collapse
1

What is the mass defect of a nucleus with binding energy \( 149.04 \, \text{MeV} \)? (Given \( 1 \, \text{u} = 931.5 \, \text{MeV/c}^2 \))

\( \Delta M = \frac{E_b}{c^2} \).

\( \Delta M = \frac{149.04}{931.5} \approx 0.16 \, \text{u} \).

0.14 u
0.15 u
0.16 u
0.17 u
3

Which process involves the splitting of a heavy nucleus into two intermediate mass fragments?

Nuclear fission is the process where a heavy nucleus splits into two intermediate mass fragments, releasing energy due to the higher binding energy per nucleon in the resulting nuclei.

Nuclear fission
Nuclear fusion
Mass-energy conversion
Thermonuclear reaction
1

What is the energy equivalent of \( 0.005 \, \text{kg} \) of matter in Joules? (Given \( c = 3 \times 10^8 \, \text{m/s} \))

\( E = m c^2 \).

\( m = 0.005 \, \text{kg} \), \( c^2 = 9 \times 10^{16} \, \text{m}^2/\text{s}^2 \).

\( E = 0.005 \times 9 \times 10^{16} = 4.5 \times 10^{14} \, \text{J} \).

4.0 × 10¹⁴ J
4.2 × 10¹⁴ J
4.5 × 10¹⁴ J
4.8 × 10¹⁴ J
3

What is the energy equivalent of \( 0.01 \, \text{kg} \) of matter in Joules? (Given \( c = 3 \times 10^8 \, \text{m/s} \))

\( E = m c^2 \).

\( m = 0.01 \, \text{kg} \), \( c^2 = 9 \times 10^{16} \, \text{m}^2/\text{s}^2 \).

\( E = 0.01 \times 9 \times 10^{16} = 9 \times 10^{14} \, \text{J} \).

8.5 × 10¹⁴ J
8.8 × 10¹⁴ J
9.5 × 10¹⁴ J
9.0 × 10¹⁴ J
4

What is the mass defect of a nucleus with binding energy \( 186.3 \, \text{MeV} \)? (Given \( 1 \, \text{u} = 931.5 \, \text{MeV/c}^2 \))

\( \Delta M = \frac{E_b}{c^2} \).

\( \Delta M = \frac{186.3}{931.5} \approx 0.2 \, \text{u} \).

0.18 u
0.19 u
0.21 u
0.2 u
4

What is the mass number of a nucleus with radius \( 5.4 \times 10^{-15} \, \text{m} \)? (Given \( R_0 = 1.2 \times 10^{-15} \, \text{m} \))

\( R = R_0 A^{1/3} \).

\( 5.4 \times 10^{-15} = 1.2 \times 10^{-15} \times A^{1/3} \).

\( A^{1/3} = \frac{5.4}{1.2} = 4.5 \).

\( A = (4.5)^3 = 91.125 \approx 91 \).

64
81
100
91
4

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