Fourier's law of heat conduction is (where Q = Amount of heat flow through the body in unit time, A = Surface area of heat flow, taken at right angles to the direction of heat flow, dT = Temperature difference on the two faces of the body, dx = Thickness of the body, through which the heat flows, taken along the direction of heat flow, and k = Thermal conductivity of the body)

• A. <img src="/_files/images/mechanical-engineering/heat-transfer-refrigeration-and-air-conditioning/404-14-1.png">
• B. <img src="/_files/images/mechanical-engineering/heat-transfer-refrigeration-and-air-conditioning/404-14-2.png">
• C. <img src="/_files/images/mechanical-engineering/heat-transfer-refrigeration-and-air-conditioning/404-14-3.png">
• D. <img src="/_files/images/mechanical-engineering/heat-transfer-refrigeration-and-air-conditioning/404-14-4.png">