GATE PH 2025 • Q48 MCQ • 2 Marks

Section 4: Quantum Mechanics

Quantum Mechanics

Subtopic: Wave Mechanics, Operators & Perturbation Theory

Question Statement:

Consider two hypothetical nuclei X1 and X2 undergoing 𝛽 decay, resulting in nuclei Y1 and Y2, respectively. The decay scheme and the corresponding JP values of the nuclei are given in the figure. Which of the following option(s) is/are correct? (J is the total angular momentum and P is parity)

Options:

  • (A) X1 → Y1 is Fermi transition and X2 → Y2 is Fermi transition
  • (B) X1 → Y1 is Fermi transition and X2 → Y2 is Gamow-Teller transition
  • (C) X1 → Y1 is Gamow-Teller transition and X2 → Y2 is Fermi transition
  • (D) X1 → Y1 is Gamow-Teller transition and X2 → Y2 is Gamow-Teller transition

Official Answer Key:

B

Step-by-Step Solution & Explanation

### **Official Solution & Step-by-Step Derivation (GATE PH 2025 Q.48)** **1. Theoretical Formulation & Physics Principles**: This question examines concepts in **Quantum Mechanics** within *Section 4: Quantum Mechanics* (2 Marks, 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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