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AP EAMCET · PHYSICS · Current Electricity

The resistance of wire at \(0^{\circ} \mathrm{C}\) is \(20 \Omega\). If the temperature coefficient of the resistance is \(5 \times 10^{-3}{ }^{\circ} \mathrm{C}^{-1}\). The temperature at which the resistance will be double of that at \(0^{\circ} \mathrm{C}\) is

  1. A \(10^{\circ} \mathrm{C}\)
  2. B \(200^{\circ} \mathrm{C}\)
  3. C \(250^{\circ} \mathrm{C}\)
  4. D \(300^{\circ} \mathrm{C}\)
Verified Solution

Answer & Solution

Correct Answer

(B) \(200^{\circ} \mathrm{C}\)

Step-by-step Solution

Detailed explanation

Resistance of wire at \(0^{\circ} \mathrm{C}, R_0=20 \Omega\) Temperature coefficient, \(\begin{aligned} & \alpha=5 \times 10^{-3}{ }^{\circ} \mathrm{C}^{-1} \\ & R_t=2 R_0=2 \times 20=40 \Omega\end{aligned}\) we know that, \(R_t=R_0(1+\alpha t)\)…