2nd Year Physics Chapter 8 Test22. Nuclear Physics

Q1. Multiple choice questions (Attempt all · 10 × 1 = 10)

1. In a fission reaction, which particle is used to bombard U-235?
   1. Alpha particle
   2. Proton
   3. Neutron
   4. Positron
2. If N is the number of undecayed nuclei, the activity is given by:
   1. A = λ/N
   2. A = N/λ
   3. A = λN
   4. A = N × T½
3. Velocity of alpha particles is approximately:
   1. Speed of light
   2. 0.05 – 0.1 c
   3. 0.5 – 0.9 c
   4. 0.001 c
4. In alpha decay, the atomic number of nucleus:
   1. Increases by 2
   2. Decreases by 2
   3. Remains same
   4. Increases by 4
5. Fusion generally occurs in:
   1. Heavy nuclei
   2. Medium nuclei
   3. Light nuclei
   4. All types of nuclei
6. The exponential law of radioactive decay is:
   1. N = N₀ eλt
   2. N = N₀ e⁻λt
   3. N = λe⁻N₀t
   4. N = teN₀λ
7. The relation between decay constant (λ) and half-life (T½) is:
   1. T½ = λ
   2. T½ = 1/λ
   3. T½ = 0.693/λ
   4. T½ = λ/0.693
8. The time taken for half of the radioactive nuclei to decay is
   1. Mean life
   2. Half-life
   3. Decay constant
   4. Activity
9. 1 Curie (Ci) is equal to:
   1. 1 × 10¹⁰ Bq
   2. 2.7 × 10¹⁰ Bq
   3. 3.7 × 10¹⁰ Bq
   4. 4.7 × 10¹⁰ Bq
10. The rods used to control the extent of nuclear reaction are called:
    1. Reactor rods
    2. Shielding rods
    3. Fuel rods
    4. Control rods