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