Thermal conductivity of a material may be defined as the: (a) Quantity of heat flowing in one second through one cubic meter of material when opposite faces are maintained at a temperature difference...

Thermal conductivity of a material may be defined as the:

(a) Quantity of heat flowing in one second through one cubic meter of material when opposite faces are maintained at a temperature difference of 1°C.

(b) Quantity of heat flowing in one second through one square meter of the area and of 1 m thickness of material when opposite faces are maintained at a temperature difference of 1°C.

(c) Both

(d) None of these