Physics Module Form 4 Chapter 4 - Heat GCKL 2011 4 - 1 4 UNDERSTANDING THERMAL EQUILIBRIUM What is thermal equilibrium ? 1. ( Heat , Temperature ) is a form of energy that flows from a hot body to a cold body. 2. The SI unit for ( heat , temperature) is Joule, J. 3. ( Heat , Temperature ) is the degree of hotness of a body 4. The SI unit for (heat , temperature ) is Kelvin, K. 5. When thermal equilibrium is reached, the net rate of heat flow between the two bodies is (zero , equal) 6. There is no net flow of heat between two objects that are in thermal equilibrium. Two objects in thermal equilibrium have the …same … temperature irrespective of shape, mass, size or type of surface. Calibration of thermometer 7. The thermometric property of an object is important in the construction of a thermometer. It is a physical quantity which is sensitive to and changes linearly with the change in temperature of the object. 4.1
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Physics Module Form 4 Chapter 4 - Heat GCKL 2011
4 - 1
4 UNDERSTANDING THERMAL EQUILIBRIUM
What is
thermal
equilibrium ?
1. ( Heat, Temperature ) is a form of energy that flows from a hot body to a cold
body.
2. The SI unit for ( heat , temperature) is Joule, J.
3. ( Heat , Temperature ) is the degree of hotness of a body
4. The SI unit for (heat , temperature) is Kelvin, K.
5. When thermal equilibrium is reached, the net rate of heat flow between the two
bodies is (zero, equal)
6. There is no net flow of heat between two objects that are in thermal equilibrium.
Two objects in thermal equilibrium have the …same… temperature irrespective
of shape, mass, size or type of surface.
Calibration of
thermometer
7. The thermometric property of an object is important in the construction of a
thermometer. It is a physical quantity which is sensitive to and changes linearly
with the change in temperature of the object.
4.1
Physics Module Form 4 Chapter 4 - Heat GCKL 2011
4 - 2
8. Lower fixed point (l 0 )/ ice point : the temperature of pure melting ice/00C
9. Upper fixed point( l 100)/steam point: the temperature of steam from water that
is boiling under standard atmospheric pressure /1000C
10. The lengths of the mercury column in the mercury-in-glass thermometer is 2.6 cm
at 0OC and 22.6 cm at 100
OC. When the thermometer is placed in hot water, the
length of the mercury column is 16.9 cm. Calculate the temperature of the hot
water.
Liquid-in-glass
thermometer
11. The liquid used in glass thermometer should
(a) Be easily seen
(b) Expand and contract rapidly over a wide range of temperature
(c) Not stick to the glass wall of the capillary tube
12. List the characteristic of mercury
(a) Opaque liquid
(b) Does not stick to the glass
(c) Expands uniformly when heated
(d) Freezing point -390C
(e) Boiling point 3570C
13. Which modification increases the sensitivity of the thermometer ?
A. Increasing the size of the bulb
B. Increasing the thickness of the bulb
C. Reducing the diameter of the capillary tube
D. Reducing the length of the capillary tube
Physics Module Form 4 Chapter 4 - Heat GCKL 2011
4 - 3
Check Yourself 1
1. The diagram below shows a thermometer is
used to measure the temperature of hot water.
When the thermometer and the hot water are in
thermal equilibrium, which of the following is
not correct ?
A. The temperature of hot water is equal to the
temperature of the thermometer
B. No heat flow between thermometer and hot
water
C. Heat flows from hot water to thermometer
D. Heat flows from thermometer to hot water
2. Which of the following characteristics does a
liquid-in-glass thermometer work ?
A. Volume of a fixed mass of liquid
B. Length of the liquid
C. Resistance of the liquid
D. Pressure of the liquid
3. Which of the following temperatures
corresponds to zero on the Kelvin scale ?
A. 273 O
C
B. 0 O
C
C. -273 O
C
D. 100 O
C
4. Diagram below shows the liquid levels from
the bulb in three thermometers P, Q and R at
certain temperatures.
What is the temperature reading at
thermometer R ?
A. 70.8 O
C
B. 65.4 O
C
C. 62.5 O
C
D. 57.7 O
C
Physics Module Form 4 Chapter 4 - Heat GCKL 2011
4 - 4
4 UNDERSTANDING SPECIFIC HEAT CAPACITY
Definition of Heat Capacity
1. Quantity of heat energy required to raise the temperature of an object by
10C.
2. The unit of heat capacity is J0C-1
3. Beaker A has (greater, same, less) heat capacity than beaker B.
4. This means that the (bigger, smaller) the mass, the (larger, smaller) the
amount of heat stored.
Definition of Specific Heat
Capacity
1. Quantity of heat energy required to raise the temperature of 1 kg of a
substance by 10C.
2. The unit of specific heat capacity is Jkg-1 0C-1
3. An object with low specific heat capacity can be heated up quickly, as it
requires less heat to increase its temperature by 10C. It can be cooled quickly
due to little amount of heat stored in it.
4. An object with high specific heat capacity takes longer time to heat up, as it
requires more heat to increase its temperature by 10C. It is harder to cool
down due to larger amount of heat stored in it.
Q = Pt
Pt = mc
Q = Heat supplied
P = Power of heater
T = Time in seconds
M = mass of substance
C = Specific heat capacity
= Increase in
temperature
4.2
A
A
B
A
Physics Module Form 4 Chapter 4 - Heat GCKL 2011
4 - 5
Determining the heat capacity
of aluminium block
1. The purpose of wrapping the aluminium blok with wool heat loss to or
absorption of heat from the surrounding.
2. Oil in the holes for housing thermometer and the immersion heater is to
improve the conduction of heat from the heater to the thermometer through
the aluminium block.
3. The immersion heater of 50 W rated power is used for 5 minutes to heat up
the aluminium block. If the mass of the alumimium block is 1.0 kg and the
rise in temperature is 160C, what is the specific heat capacity of aluminium ?
15000937.5
1 16
PtC
m
Jkg-10C-1
4. Specific heat capacity calculated is usually larger than the standard value
because some heat is lost to the surroundings.
Aim To investigate the relationship between temperature rise and mass of water
Experiment
Hypothesis When the mass of water …increases… the temperature rise will …decrease….
Manipulated variable Mass of water
Responding variable Rise in temperature
Fixed variable Heating duration, water, weighing scale, power rating of heater used