

| Column $-\,I$ | Column $-\,II$ |
| $(a)$ Wein's constant | $(i)$ $Wm^{-2}\,K^{-4}$ |
| $(b)$ Stefan-Boltzmaan's constant. | $(ii)$ $Wm^{-1}\,K^{4}$ |
| $(iii)$ $mK$ |

If heat flows through them from $x = 0$ to $x = 2L$ at a steady rate and conductivities of the metals are $K_{cu}$ and $K_{steel}$ $(K_{cu} > K_{steel}),$ then the temperature varies as (convection and radiation are negligible)