
| Column $- I$ | Column $- II$ |
| $(A)$ Drift Velocity | $(P)$ $\frac{m}{n e^{2} \rho}$ |
| $(B)$ Electrical Resistivity | $(Q)$ $\mathrm{ne} v_{\mathrm{d}}$ |
| $(C)$ Relaxation Period | $(R)$ $\frac{\mathrm{eE}}{\mathrm{m}} \tau$ |
| $(D)$ Current Density | $(S)$ $\frac{E}{J}$ |

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 $27^{\circ} C$ to $227^{\circ} C$. This implies that $\alpha=2.5$ $\times 10^{-3} /{ }^{\circ} C$
statement$-2\;: R=R_{0}(1+\alpha \Delta t)$ is valid only when the change in the temperature $\Delta T$ is small and $\Delta R=\left(R-R_{0}\right) < < R_{0}$


