Question

What factors affect the ability of a substance to transfer thermal energy to heat or be heated by it's surroundings?

Answer 1

The prime factors that affect the ability of substances to transfer the thermal energy to heat are the temperature difference between the two objects, area of cross-section, time, and distance travelled by the thermal energy.

Explanation:

The process of heat conduction takes place through contact between two or more objects. But this conduction depends on multiple factors that are responsible for thermal conduction. They are-

• Temperature Difference($\Delta T$) - The two objects must have a temperature difference else there will be no thermal conduction between them. The more the difference in their temperatures, the more thermal energy flows from one object to the other.
• Area of Cross-section (A) - Larger areas of contact provide as better medium of thermal conduction.
• Time (t) - The more time we give for the thermal conduction, the more energy is transmitted from one system to the other.
• Distance Travelled (l) - The longer the distance, lesser the conduction. Means, the distance should be minimized in order to achieve the optimum thermal conduction between two objects.

Consider metal pot and its handle, it is being boiled for 15 m. The molecules present near the source of heat, showing fast vibration and bounce off. It actually indicates the heats of substance. That’s why, handle remains hot as heat conduction takes place.  It can be estimated by,

                                       $Q=\frac{k A \Delta T t}{l}$

k - Thermal conductivity of the material, measured in J/s.m.$^{\circ} \mathrm{C}$