# Specific heat capacity

video for types of thermometer

Specific heat capacity is the amount of heat required to change the heat content of exactly 1 gram of a material by exactly 1°C.

Here is a table for SHC of some materials:

 S.No. Materials 'S' in Jkg-1°C-1 1. Lead 126 2. Gold 130 3. Mercury 140 4. Silver 234 5. Brass 380 6. Copper 380 7. Steel 447 8. Alcohol 2590 9. Water 4200 10. Petrol 1670

Some effects of Specific Heat Capacity are:

• Water is used to cool the engines of vehicles.

• Water is suitable for heating systems.

• The night in the desert is very cold while the day is very hot.

• Sea breeze occurs in the day and land breeze occurs at night.

﻿Heat Equation

﻿Let the temperature of a body of mass 'm' raises from t to t, when it is heated by supplying the amount of heat Q.

Here, the mass of the body= m

Initial temperature=t1
Final temperature=t2
Amount of heat supplied= Q

∴ Change in temperature(dt)= t2-t1

It has been found that heat gained or lost by a body is directly proportional to (I) the mass of the body and (II) the change in temperature.

∴ Q m....... (I)

Q dt....... (II)

Combining equations (I) (II), we have

﻿Q mdt

∴ Q= Smdt

or, Q= mSdt..........(III)

﻿Principle of Calorimeter

﻿The principle of calorimeter states that for an insulated system, heat energy lost by a hot body is equal to the heat gained by the cold body.

∴Heat lost                                                  = Heat gained...........(I)
﻿(by a body at a higher temperature)          (by a body at a lower temperature)
or, m1 * S1 * dt1                                               = m2 * S2 * dt2