Assertion: In a pressure cooker the water is about to be boiled. The cooker is then removed from the stove. Now on removing the lid of the pressure cooker, the water boils again.Reason: The impurities in water bring down its boiling point.

Thermodynamics is a branch of physics that studies the relationship between heat, work, and temperature, and how they relate to energy, entropy, and the physical properties of matter and radiation.  Specific heat is the amount of heat needed to raise the temperature of 1 gram of a substance by 1 degree Celsius. It is also known as massic heat capacity.  The units of specific heat are usually calories or joules per gram per Celsius degree. For example, the specific heat of water is 1 calorie (or 4.186 joules) per gram per Celsius degree.  Specific heat is a property of the substance. Its SI... Show more

Thermodynamics is a branch of physics that studies the relationship between heat, work, and temperature, and how they relate to energy, entropy, and the physical properties of matter and radiation. 

Specific heat is the amount of heat needed to raise the temperature of 1 gram of a substance by 1 degree Celsius. It is also known as massic heat capacity. 
The units of specific heat are usually calories or joules per gram per Celsius degree. For example, the specific heat of water is 1 calorie (or 4.186 joules) per gram per Celsius degree. 
Specific heat is a property of the substance. Its SI unit is J/(kg⋅K) or J/(kg⋅C). 
Specific heat is helpful in determining the processing temperatures and amount of heat necessary for processing. It can also be helpful in differentiating between two polymeric composites. 
As the substance heats up, the average kinetic energy of the molecules increases. The collisions provide enough energy to allow rotation to happen. Rotation then adds to the interior energy and raises the specific heat. 

Show less