# Physics Course/Heat

## Sources of Heat

Generally, Heats come from different sources

• Fire .
Chemical Reaction between two flammable or combustible materials
• Celestial Body's Lights
Sun light produce Heat as a Light of hot temperature. Moon Light produce Heat as a Light of Cold Temperature
• Electric Light
Conductors when conduct current will change their body temperatures and release Heat Energy and Light

## Heat

Heat is caused by friction . When rubbing two objects the object bodies will change in temperatures which produces Heat .

## Temperature

Temperature is a measured of Heat denoted as T measured in Degree . There are three system of temperature measurements namely Degree C , Degree F , Degree K

System of Measuring Temperature Temperature of Freezing Point Temperature of Boiling Point Room Temperature
Degree C 0o 100o 25o
Degree F 32o 212o 77o
Degree K 273.16 373.16 298.16

## Heat and Matters

An object when absorbs heat exhibit the followings

1. Change in object's Temperature
2. Change object's state or form
3. Release Heat's Energy in the surrounding as Light

When an object absorbs Heat's Energy, it will change its temperature and either expand or shrink itself.

For example, Electric wire shrink in the winter and expand in the summer .

## Thermodynamic Law of Heat Transfer

### First Law of Thermodynamic

When an object absorbs heat's energy it will expand or shrink

If an object has a Mass m at the normal temperature of To . When this object absorbs heat's energy it will change its body temperature to T . Therefore the change in temperature of the object is T - To . If the object has an absorption constant of C then Heat Transfer can be calculated as
Q = m C (T - To) = m C ΔT

### Second Law of Thermodynamic

Heat transfer from objects that has a high temperature to object that has a low temperture

E = 0 When $T_{1}=T_{2}$
E > 0 When $T_{1}>T_{2}$
E < 0 When $T_{1}

## Summary

Heat comes from differenct sources namely Fire , Light , Electric or from collision of two objects . Temperature is a measured of Heat denoted as T measured in Degree .

There are three system of temperature measurements namely Degree C , Degree F , Degree K

System of Measuring Temperature Temperature of Temperature of Room Temperature
Degree C 0o 100o 25o
Degree F
Degree K

The laws govern Thermaldynamic of Heat transfer are listed in the table below

Thermodynamic Law Heat Transfer Formula
Thermodynamic First Law Heat is absorbed by matter that either make matter to shrink or to expand Q = m c (T - To)
Thermodynamic Second Law Heat transfer from High temperature to low temperature . From Hot to Cold E = Q1 - Q2 khi T1 > T2
E = Q2 - Q1 khi T2 > T1

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