Preparation |
Just what you need to know ! |
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**Sensible heat** is the heat gained or lost by a body resulting in a change in temperature.
**Latent heat** or hidden heat is the heat gained or lost by a body during a change of state when it does not result in any change in temperature.
**Heat capacity** or thermal capacity of a body is defined as the amount of heat required to raise its temperature by 1^{o}C.
The SI unit of heat capacity is J/^{o}C (Joules per degree Celsius).
**Specific heat capacity** of a substance is defined as the amount of heat required to raise the temperature of a unit mass of it by 1 ^{o}C.
**∴ Specific Heat Capacity = Heat capacity / Mass.**
The SI unit of specific heat capacity is J/(kg ^{o}C).
However, a commonly used unit is J/(g ^{o}C).
**Water** has a specific heat capacity of about 4.2 J/(g ^{o}C), or 4200 J/(kg ^{o}C) in SI units.
More accurately, the specific heat capacity of water is 4.184 J/(g ^{o}C) or 4184 J/(kg ^{o}C).
The very high value for the specific heat capacity of water is responsible for land breezes, sea breezes and the weather.
**The amount of sensible heat** gained or lost by a body is given by the product of its heat capacity (mass × specific heat capacity) and the temperature change.
Thus, the formula worth-remembering is:
*Q* = *m* × *c* × (*t*_{1} − *t*_{2}), where
*Q* is the amount of sensible heat gained or lost by the body,
*m* is the mass of the body,
*c* is the specific heat capacity of the material, and
*t*_{1} and *t*_{2} are the two temperatures denoting the temperature change.
Physics Quiz on Sensible Heat & Heat Capacity. |