Question

The temperature coefficient of resistance ot a wire is $0.00125 \, per \,{}^\circ C$. At 300 K temperature its resistance is $1\Omega$. The resistance of the wire will be $2\Omega$ at

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

Answer 1

Answer: (D)

$\frac {R_1}{R_2}=\frac {1+\alpha t_1}{1+\alpha t_2}$
$\Rightarrow \frac {1}{2}=\frac {(1+0.00125 \times 27)}{(1+0.00125 \times t)}$
$\Rightarrow t={854}^\circ C$
$\Rightarrow $ T=1127K