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Physics · 2024 · 2 marks
CBSE 2024 · Region 1 · Set 1 · Q17
Find the temperature at which the resistance of a wire made of silver will be twice its resistance at 20^° C. Take 20^° C as the reference…
Find the temperature at which the resistance of a wire made of silver will be twice its resistance at $\displaystyle 20^{\circ} \mathrm{C}$. Take $\displaystyle 20^{\circ} \mathrm{C}$ as the reference temperature and temperature coefficient of resistance of silver at $\displaystyle 20^{\circ} \mathrm{C}=4.0 \times 10^{-3} \mathrm{~K}^{-1}$.
Marking-scheme solution
\[\mathrm{R}=\mathrm{R}_{\circ}\left[1+\alpha\left(T-T_{\circ}\right)\right]
\] \(\displaystyle \mathrm{R}=2 \mathrm{R}_{\mathrm{o}}\) [Given]
\[2 \mathrm{R}_{\circ}=\mathrm{R}_{\circ}\left[1+\alpha\left(T-T_{\circ}\right)\right]
\]
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