Physics Vidyapith ✍️

Heat : 1. Heat is that form of energy which flows from a hot body to a cold body when they are kept in contact. 2. The S.I unit of heat is $joule (J)$. 3. The amount of heat contained in a body depends on mass, temperature and substance of body. 4. Heat of the body is measured by the principle of calorimetry. 5. Two bodies having same amount of heat may differ in their temperature. 6. When two bodies are placed in contact then the total amount of heat is equal to the sum of heat of individual body. Temperature: 1. Temperature is a parameter that determines the direction of the flow of heat while keeping the two bodies at different temperatures in contact. 2. The S.I. unit of temperature is $kelvin (K)$. 3. The temperature of a body depends on the average kinetic energy of its molecules due to their random motion. 4. Temperature of the body is measured by a thermometer. 5. Two bodies at the same temperature may differ in the quantities of heat con

Heat capacity: 1. Heat capacity is the amount of heat energy required to raise the temperature of the entire body by $1^{\circ}C$. 2. Heat capacity depends both on the nature of the substance and the mass of the body. As the mass of the body increases the heat capacity of the body also increases. 3. Heat capacity $C=\frac{Q}{\Delta t}\\ C = mass (m) \times specific \: heat \: capacity (c)$ 4. The unit of Heat capacity is $J-K^{-1}$. Specific heat capacity: 1. Specific heat capacity is the amount of heat energy required to raise the temperature of the unit mass of the body by $1^{\circ}C$. 2. Specific heat capacity does not depend on the mass of the body, but it is the characteristic property of the substance of the body. 3. Specific heat capacity $C=\frac{Q}{m\Delta t} \\ C=\frac{Heat \: Capacity \: (C)}{Mass (m)}$ 4. Its unit is $J-kg^{-l}-K^{-1}$.

Isothermal Process: 1.) In this process temperature remains constant i.e.$(\Delta T= 0)$. 2.) In this process internal energy remains constant i.e. $(\Delta U= 0)$. 3.) This process takes place very slowly. 4.) In this process the system is surrounded by a perfectly conducting material, whose conductivity is infinite. 5.) This process obeys Boyle's law i.e. $(PV= constant)$. 6.) In this process the slope of isothermal curve $=-\frac{P}{V}$ 7.) In this process specific heat of gas should be infinite. Adiabatic Process: 1.) In this process exchange of heat does not take place i.e. $(\Delta Q= 0)$ but temperature changes. 2.) In this process internal energy changes. 3.) This process takes place very rapidly. 4.) In this process the system is surrounded by a perfectly insulating material, whose conductivity is zero. 5.) This process obeys Poisson's law i.e. $(PV^{\gamma} = constant)$. 6.) In this process the slope of adiabatic curve $=-