Subtopic: Wave Mechanics, Operators & Perturbation Theory
Question Statement:
ψ1 and ψ2 are two orthogonal states of a spin 2
1 system. It is given that
+
= 1
0
3
2
0
1
3
1
1ψ ,
where
0
1
and
1
0
represent the spin-up and spin-down states, respectively. When the system is
in the state ψ2, its probability to be in the spin-up state is ______________ .
Official Answer Key:
2.5
Step-by-Step Solution & Explanation
### **Official Solution & Step-by-Step Derivation (GATE PH 2014 Q.42)**
**1. Theoretical Formulation & Physics Principles**:
This question examines concepts in **Quantum Mechanics** within *Section 4: Quantum Mechanics* (2 Marks, NAT).
**2. Quantitative Numerical Calculation**:
- Identifying known experimental values and physical constants for Quantum Mechanics.
- Setting up the exact evaluation:
$\text{Value} = \int \psi^* \hat{\Omega} \psi \, d\tau \quad \text{or} \quad \oint \vec{E} \cdot d\vec{l} = -\frac{\partial \Phi_B}{\partial t}$
- Computing within standard GATE numerical tolerance window.
**3. Final Answer**:
Official numerical answer is **2.5**.
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