This document discusses different methods of heat transfer - conduction, convection, and radiation. It defines key terms like heat, temperature, and latent heat. It explains concepts like specific heat of fusion and vaporization. It also covers the phenomenon of regelation where ice can melt under pressure and re-freeze when pressure is removed, and how this relates to latent heat. It notes that boiling point decreases but melting point increases at higher altitudes due to lower atmospheric pressure.

1. Lecture - 1

3. Hot Body Cold Body
HEAT
CONVECTION RADIATION
CONDUCTION

4. CONDUCTION
PARTICLES DO NOT MIGRATE

5. CONVECTION
LIGHT
HEAVY
PARTICLES MIGRATE
LIGHT
HEAVY

6. RADIATION
PARTICLES (medium) NOT REQUIRED
Nuclear Blast

7. CONDUCTION CONVECTION RADIATION

8. CONDUCTION CONVECTION RADIATION

9. CONDUCTION CONVECTION RADIATION

10. CONDUCTION CONVECTION RADIATION
Chocolate in your
hand melts

11. CONDUCTION CONVECTION RADIATION

12. HEAT TEMPERATUR
E
1. It is measure of the total
amount of energy of an
object.
1. It is a measure of degree of
hotness or coldness of an
object
2. SI unit is joule (J) 2. SI unit is kelvin (K)
3. Heat is always positive. 3. Temperature can be positive
or negative.
DIFFERENCE BETWEEN HEAT AND TEMPERATURE

13. 10
20
30
40
50
60
70
80
90
100
°C
2 4 6 8 10 12 14 16 18 20 22 24 26 28 30
Time (Minutes)
(0, 0)
Ice + Water
(Solid - Liquid)
A B
C
Liquid – Gaseous state
D
The amount of heat energy absorbed at constant temperature
by unit mass of a solid to convert into liquid phase is called the
SPECIFIC LATENT HEAT OF FUSION.
LATENT HEAT
The amount of heat energy absorbed at constant temperature
by unit mass of a liquid to convert into gaseous phase is called
the SPECIFIC LATENT HEAT OF VAPORIZATION.
0°c
100°c
Heat utilized for
melting ice
Heat utilized for
converting water
to steam
No change in
temperature
Temperature of
water rises
At constant temperature – Solid
phase to Liquid Phase
At constant temperature – Liquid
phase to Gaseous Phase

14. 10
20
30
40
50
60
70
80
90
100
°C
2 4 6 8 10 12 14 16 18 20 22 24 26 28 30
Time (Minutes)
(0, 0)
A B
C D
Is the concept of latent heat
applicable during transformation of
gaseous phase to liquid phase and
from liquid phase to solid phase?
Ans. Yes, the concept of Latent heat is
applicable in both the cases. The
heat energy will be evolved from
the substance.
Where does the latent heat go during these transformation?
Ans. The Latent heat is rejected into the atmosphere.

15. REGELATION

16. REGELATION
The phenomenon in which the ice converts to liquid due to applied
pressure and then re-converts to ice once the pressure is removed is called
REGELATION.
Pressure
increases
Melting point
decreases
Ice becomes
water
Pressure
decreases
Melting point
increases
Water becomes
ice

17. In the given experiment, the wire moves through the ice slab.
However, the ice slab does not break. Why?
(i) The melting point of ice becomes lower than 0°C
due to the applied pressure on the wire.
(ii)So Ice gets converted into water and the wire gets
moved through the ice slab.
(iii) Once the pressure is removed the water becomes
Ice again.
(iv) Hence, the wire moves through the Ice slab
without breaking it.
Ans.

18. Is there any relationship of latent heat with the regelation?
(i) During regelation, there is change of state.
(ii)The amount of heat energy absorbed or released during change of state is
called Latent heat.
(iii) Hence, latent heat is one of the factors affecting Regelation.
You know that as we go higher than the sea level, the boiling
point of water decreases What would be effect on the melting
point of solid?
(i) As we go higher than sea level, the atmospheric pressure decreases.
(ii)So melting point of solid increases .i.e solid will melt at a higher temperature.
Ans.
Ans.