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CUET · PHYSICS · PYQ PAPER 2025

A wire has a resistance of \( 3 \text{ } \Omega \) at 20°C and \( 5 \text{ } \Omega \) at 100°C. The temperature coefficient of resistance of the wire is:

  1. A \( 0.00833 \text{ } ^\circ\text{C}^{-1} \)
  2. B \( 0.0125 \text{ } ^\circ\text{C}^{-1} \)
  3. C \( 0.0025 \text{ } ^\circ\text{C}^{-1} \)
  4. D \( 0.0012 \text{ } ^\circ\text{C}^{-1} \)
Verified Solution

Answer & Solution

Correct Answer

(A) \( 0.00833 \text{ } ^\circ\text{C}^{-1} \)

Step-by-step Solution

Detailed explanation

\( \alpha = \frac{R_2 - R_1}{R_1(T_2 - T_1)} \) \( \alpha = \frac{5 \text{ } \Omega - 3 \text{ } \Omega}{3 \text{ } \Omega (100^\circ\text{C} - 20^\circ\text{C})} \) \( \alpha = \frac{2}{3(80)} \text{ } ^\circ\text{C}^{-1} \) \( \alpha = 0.00833 \text{ } ^\circ\text{C}^{-1} \)
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