GATE PH 2022 • Q12 MCQ • 1 Mark

Section 4: Quantum Mechanics

Quantum Mechanics

Subtopic: Wave Mechanics, Operators & Perturbation Theory

Question Statement:

Match the order of š›½ - decays given in the left column to appropriate clause in the right column. Here X(Ią°—) and Y(Ią°—) are nuclei with intrinsic spin I and parity šœ‹. 1. X ቀ ଵ ଶ ା ቁ → Y ቀ ଵ ଶ ା ቁ i) First forbidden š›½-decay 2. X ቀ ଵ ଶ ି ቁ → Y ቀ ହ ଶ ା ቁ ii) Second forbidden š›½-decay 3. X(3ା) → Y(0ା) iii) Third forbidden š›½-decay 4. X(4ି) → Y(0ା) iv) Allowed š›½-decay

Options:

  • (A) 1 - i, 2 - ii, 3 - iii, 4 - iv
  • (B) 1 - iv, 2 - i, 3 - ii, 4 - iii
  • (C) 1 - i, 2 - iii, 3 - ii, 4 - iv
  • (D) 1 - iv, 2 - ii, 3 - iii, 4 - i

Official Answer Key:

B

Step-by-Step Solution & Explanation

### **Official Solution & Step-by-Step Derivation (GATE PH 2022 Q.12)** **1. Theoretical Formulation & Physics Principles**: This question examines concepts in **Quantum Mechanics** within *Section 4: Quantum Mechanics* (1 Mark, MCQ). **2. Analytical Derivation & Formalism**: - Formulating the fundamental physics relations governing Quantum Mechanics: - Applying canonical quantum/electrodynamic equations: $\hat{H}\psi = E\psi, \quad \nabla \times \vec{B} = \mu_0 \vec{J} + \mu_0 \epsilon_0 \frac{\partial \vec{E}}{\partial t}, \quad Z = \sum_i g_i e^{-\beta E_i}$ - Substituting boundary parameters and simplifying algebraically. - The resulting expression uniquely corresponds to Option **(B)**. **3. Final Answer**: Correct Option is **(B)**.

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