Question

The temperature co-efficient of resistance of a wire is $0.00125{/}^{\circ }C$. At 300 K , it’s resistance is $1\Omega$. The resistance of the wire will be $2\Omega$ at

• A. 1154 K
• B. 1127 K
• C. 600 K
• D. 1400 K

Answer 1

The correct option is B 1127 K

By using $R_t=R_0(1+\alpha \Delta t)\Rightarrow \frac{R_1}{R_2}=\frac{1+\alpha t_1}{1+\alpha t_2}$ So $\frac{1}{2}=\frac{1+(300-273)\alpha }{1+\alpha t_2}\Rightarrow t_2={854}^{\circ }C=1127K$