Question

State whether the given statement is true or false.
Heat always flows from a body at lower temperature to a body at higher temperature.
A. True
B. False

Answer 1

Hint: Heat is defined as the energy which is transferred from or to a thermodynamics system. Heat is transferred from one body to the other by the mechanism of thermodynamic work or the transfer of matter.

Complete answer:
There are three different mechanisms of transfer of heat from one body to the other. These three mechanisms are explained below:

Conduction:
Conduction is the process of transfer of heat by the collisions of particles of gas or liquid. An area having greater kinetic energy to the area having lower kinetic energy. The higher-speed particles will collide with the particles having slower speed, as a result, the collision will increase the kinetic energy of the slower-speed particles. Cross-section area of an object and path travelled are the important factors in the process of conduction. The greater the size of an object, the more heat will be lost.

Convection:
Convection is the process in which the thermal energy or heat is carried away from the source of heating. When we heat a fluid, the fluid above the surface of the bowl will become less dense and will rise up.

Thermal radiation:
Thermal radiation is the process of transfer of heat by the emission of electromagnetic waves. Thermal radiation is the result of the random movement of the atoms and molecules. These waves will carry the heat away from the emitting object.
Thermal energy of all the materials is directly proportional to the temperature of the material. Therefore, the higher the temperature of an object, the more heat will be released.

Therefore, from the above mechanisms, heat released by the body at high temperature is greater than the heat released by the body at low temperature. Therefore, the heat flows from the body at higher temperature to the body at lower temperature.

Hence, the above statement is false.Thus option B is the correct answer.

Note:Heat transfer is the process in which more than one body is involved. In thermodynamics, the transfer of heat will change the internal energy of the system and the variable of state of a function. The heat evolved can be determined by using the first law of thermodynamics.