(i) A potential difference of 200 volt is applied to a coil at a temperature of `15^(@)C` and the current is 10 A. What will be the temperature of the coil when the current has fallen to 9 A, the applid voltage being the same as before ? Temperature coefficient of resistance ` (alpha)=1/(234).^(underline(o))C^(-1)`.
(ii) A platinum wire has resistance of 10 ohm at `0^(@)C` and 20 ohm at `273^(@)C`. Find the value of temperature coefficient of resistance.

Answer

(i)` 41^(underline(@))C,`
(ii) `(ln2)/(273).^(underline(@))C^(-1)`