Define coefficient of thermal conductivity and temperature gradient.

Explanation

``The coefficent of thermal conductivity ``(K) it is the quantity of heat flowing normally per second through unit area of the substance per unit temperature gradient.
`K=(Q.L)/(A(theta_(2)-theta_(1)t)`
``Temperature gradient `` is defined as the change in temperature along the conductor per unit length. Temperature gradient
Change in temperature
`("between the ends")/("Length of conductor")=(0_(2)-0_( 1))/(1)`