JEE Main 2009 — Current Electricity Question with Solution

This question contains Statement-1 and Statement-2. Of the four choices given after the statements, choose the one that best describes the two statements. Statement-1: The temperature dependence of resistance is usually given as $R=R_0(1+\alpha \Delta t)$. The resistance of a wire changes from $100\Omega$ to $150\Omega$ when its temperature is increased from $27^{\circ }\mathrm{C}$ to $227^{\circ }\mathrm{C}$. This implies that $\alpha =2.5\times 10^{-3}/{}^{\circ }\mathrm{C}$. Statement 2: $R=R_i(1+\alpha \Delta T)$ is valid only when the change in the temperature $\Delta T$ is small and $\Delta R=$ $\left(R-R_0\right)\ll R_0$.