Subtopic: Crystal Lattices, Band Theory & Superconductivity
Question Statement:
Neutrons moving with speed 103 m/s are used for the determination of crystal structure. If the Bragg
angle for the first order diffraction is 300, the interplanar spacing of the crystal is _________ Å.
(Given: mn = 1.675 × 10-27 kg, ℎ = 6.626 × 10-34 JJ. ss)
PH 8/10
PH (GATE 2014)
1 PHYSICS-PH
Official Answer Key:
2.5
Step-by-Step Solution & Explanation
### **Official Solution & Step-by-Step Derivation (GATE PH 2014 Q.43)**
**1. Theoretical Formulation & Physics Principles**:
This question examines concepts in **Solid State Physics** within *Section 7: Solid State Physics* (2 Marks, NAT).
**2. Quantitative Numerical Calculation**:
- Identifying known experimental values and physical constants for Solid State Physics.
- 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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