Q. Resistance of tungsten wire at $150℃$ is $133\Omega.$ Its resistance temperature coefficient is $0.0045/℃.$ The resistance of this wire at $500℃$ will be
A) $180\Omega$
B) $225\Omega$
C) $258\Omega$
D) $317\Omega$
Explanation
(c) $\frac{R_{150}}{R_{500}} = \frac{\left\lbrack 1 + \alpha(150) \right\rbrack}{\left\lbrack 1 + \alpha(500) \right\rbrack}.$ Putting $R_{150} = 133\Omega$ and
$\alpha = 0.0045/℃$, we get $R_{500} = 258\Omega$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.