Question

The temperature coefficient of resistance for a wire is 0.00125${/}^{\circ }C$. At 300K its resistance is 1 ohm. The temperature at which the resistance becomes 2 ohm is

• A. 1154 K
• B. 1100 K
• C. 1400 K
• D. 1127 K

Answer 1

The correct option is D 1127 K

$\frac{{\rho }_1}{{\rho }_2}=\frac{(1+\alpha t_1)}{(1+\alpha t_2)}=\frac{1}{2}\Rightarrow \frac{(1+0.00125\times 27)}{(1+0.00125\times t)}$

$\Rightarrow t={854}^{\circ }C\Rightarrow T=1127K$