Physics Quiz (Q11–Q20)
Q11: In which radioactive disintegration neutron dissociates into proton and electron?
A) α-emission
B) β-emission
C) γ-emission
D) None of these
Explanation: In β-emission, neutron transforms: ¹n → ¹H + e⁻ + ν̄.
Q12: A nucleus emits two α-particles and two β-particles and transforms into a thorium nucleus. What are the mass and atomic numbers?
A) 230, 90
B) 230, 88
C) 234, 90
D) 234, 88
Explanation: ²³⁵U → 2α → X → 2β → ²³⁰Th.
Q13: Specify the parent, daughter nuclei and emitted particle in given reaction.
A) Parent: Th, Daughter: U, Emitted: Neutron
B) Parent: U, Daughter: Th, Emitted: Neutron
C) Parent: Th, Daughter: U, Emitted: Alpha
D) Parent: U, Daughter: Th, Emitted: Alpha
Explanation: Parent is ²³⁸U, daughter is ²³⁴Th, emitted particle is α.
Q14: A nucleus decays by 2β and α emission. Effect on proton and nucleon numbers?
A) Proton ↑, Nucleon ↓
B) Proton ↓, Nucleon ↑
C) Proton unchanged, Nucleon ↓
D) Proton ↓, Nucleon unchanged
Explanation: Net proton unchanged, nucleons decrease.
Q15: α-particle bombarded on ¹⁴N forms ¹⁷O. The emitted particle is:
A) Neutron
B) Electron
C) Proton
D) Positron
Explanation: ¹⁴N + ⁴He → ¹⁷O + ¹H.
Q16: If ²³³U decays twice by α-emission, the resulting isotope will be:
A) ²²⁵Ra₈₈
B) ²³⁴Pa₈₈
C) ²²⁵Rn₈₆
D) ²²⁹Th₉₀
Explanation: ²³³U → 2α → ²²⁵Ra.
Q17: Sequence of decays: ²¹⁷At → V → W → X (2α + 1β). What is X?
A) ²¹³At
B) ²⁰⁹Pb
C) ²¹⁵Ir
D) ²¹⁷Tl
Explanation: ²¹⁷At → α → ²¹³Bi → α → ²⁰⁹Tl → β → ²⁰⁹Pb.
Q18: Radon-220 decays to Polonium-216 by α-emission. Neutrons in radon and polonium?
A) 86, 84
B) 134, 132
C) 220, 216
D) 220, 216
Explanation: Neutrons = A−Z → Rn: 220−86=134, Po: 216−84=132.
Q19: In α-decay, ratio of decrease in proton to neutron number is:
A) 2 : 1
B) 1 : 1
C) 1 : 2
D) 4 : 1
Explanation: α emission removes 2 protons & 2 neutrons → ratio 1:1.
Q20: ²²²Rn decays by α- and β-emission to ²¹⁴Bi. How many α and β emitted?
A) 1, 1
B) 2, 1
C) 1, 2
D) 2, 2
Explanation: ²²²Rn → 2α → ²¹⁴Pb → 2β → ²¹⁴Bi → 2 α & 2 β emitted.
.png)
0 Comments