College Physics with Mastering Physics
Physics & Astronomy
Quiz 10 :
Temperature and Kinetic Theory
Heat always flows from a hot body (high temperature) to cold body (low temperature), if they are in thermal contact. When a body is heated its internal energy increases, motion of inner particles of body increases. But internal energy is function of mass and specific heat too. Mass and specific heat depends on composition of material may be different for different materials. Suppose a material has high temperature but the values of its mass and specific heat are less that means it has low internal energy and another material has low temperature more mass and specific heat. If these two are in thermal contact heat will flow from material of high temperature to low temperature. So it is not necessary that heat always flow from a body of more internal energy to low internal energy.
The kinetic energy of ideal gases is, Here, is Boltzmann's constant and T is temperature. Root mean square velocity is, In above formula, the kinetic energy is dependent upon the temperature. Also, momentum is, Substitute for , Thus, momentum is also dependent on temperature. Also, potential energy contributes to the total internal energy which is Here, is molar heat capacity and denotes the change in temperature. Thus, it also depends upon temperature. Thus, (a), (b) and (c) are incorrect options. Hence, the correct option is .