1. HEAT Sumber Gambar : site: gurumuda.files.wordpress.com
Sumber Gambar Fisika SMK Teknologi, Direektorat SMK

2. Heat
Heat Definition
“ the energy flowing from the hotter bodies to the colder bodies when they are in contact each other until their temperatures are identical and thermal equilibrium is reached“
Heat
energy
form
The motion of atom, molecules & other particles which comprise a matter
Related with
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definition

3. Specific heat and heat capacity
Heat capacity is the amount of heat required by an object to change its temperature of 1o C atau 1 K.
Q = Heat ( Joule )
T = change of temperature (o C atau K )
C = heat capacity ( Jolue/ o C atau Jolue/ K)
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head capacity

4. Specific heat and heat capacity
The specific heat is the amount of heat (in calories) that is required to raise the computer of one gram of a substance one degree Celcius or one Kelvin
c = specific heat ( Jolue/KgoC atau Jolue/Kg K)
m = mass (Kg)
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specific heat

5. Specific heat of several substances (at 20 ºC and 1 atm)
(J/kg K)
Molar specific heat
(J/mol K)
Gold
130
25,6
Lead
26,8
Mercury
140
28,0
Copper
385
24,4
Aluminum
900
24,3
Water
4190
75,4
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specific heat

6. Conservation energy law for heat
Conservation energy law for heat complies the principle proposed by Joseph Black, so is called the Black’s principle.
“when mix two substance, the amount of heat released by the higher temperature substance is equal with the amount of heat absorbed by the lower temperature substance ”. TA TB
TA > TB T
A releases the heat &
B absorbs the heat
Qreleased = Qabsorbed
Both of final temperature (T) are same (equal)
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Black’s principle

7. Change of phase
Gas
liquid
solid
Condensation
freezing
evaporating
sublimation
The change of phase of a substance is caused by the substance releasing heat
The change of phase of a substance is caused by the substance absorbing heat
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change of phase

8. Melting latent heat (melting heat) boiling latent heat (boiling heat)
Latent heat (L)
Latent is the amount of heat that required to change 1 kg phase of substance at a constant temperature
Melting latent heat (melting heat)
Freezing latent heat (freezing heat) =
latent heat(L)
Q = heat (J)
m = substance mass zat (Kg)
boiling latent heat (boiling heat)
condensation latent heat (condensation heat) =
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latent heat

9. Factors influencing the change of phase
P increase
Its boiling point increases
Pressure (P)
Factors influencing the change of phase
Its boiling point increase
Impurity of substance
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change of phase

10. Heat transfer
Heat tends to move from higher temperature to lower temperature region
solid
Conductor
conduction
Isolator
Heat transfer
Convection
Liquid & gas
solid
Radiation
liquid & gas
vaccum
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heat transfer

11. Conduction TB TC A = surface area (m2) TB= temperature at point B A
Conduktion occurs because one particle (atom or molecule) vibrates and interacts with the neighboring atoms or molecules.
A = surface area (m2) d A TB TC
d = length/thickness of substance(m)
TB= temperature at point B
TC= temperature at point C
k = thermal conductivity (W/mK)
t = time (second)
Speed of conduction heat
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conduction

12. TB= temperature at point B TC= temperature at point C
Convection
Convection occurs because of the fluid flow that is different in density, such as refrigerator & hair drier d A
fluid TC TB
A = surface area (m2)
TB= temperature at point B
TC= temperature at point C
h = coeffisien of convection (W/m2K)
speed convection heat
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convection

13. Stefan-Boltzmann’s Law = constanta of Stefan-Boltzman
Radiation
Radiation is one mechanism of heat transfer in the form of electromagnetic waves without passing through a medium. For example, heat of sun can reach earth.
e = emissivity ( 0  e  1 )
Perfect blackbody, e = 1
Perfect whitebody, e = 0 T A
Stefan-Boltzmann’s Law
= constanta of Stefan-Boltzman
(5,67x10-8 W/m2K4)
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radiation