Answers to end-of-chapter questions
Chapter 10
1 a Liquid in bulb absorbs energy; gets hotter;
7 a Mercury expands as its temperature
expands; pushes up tube.
b melting point of pure ice (0 °C); boiling
point of pure water (100 °C)
2 a A has greater range (120 °C, from −10 °C to
+110 °C).
(B’s range is only 60 °C, from −10 °C
to +50 °C.)
b B is more sensitive. Each degree is a wider
interval on the scale, so smaller changes
can be measured.
3 solids, liquids, gases
4 more, greater
or less, smaller
5 a specific heat capacity – the energy required
per kilogram and per degree celsius to raise
the temperature of a substance.
b specific latent heat of fusion – the energy
per kilogram required to cause a substance
to change state from solid to liquid at its
melting point.
c specific latent heat of vaporisation – the
energy per kilogram required to cause a
substance to change state from liquid to
gas at its boiling point.
6 a energy = mass × specific heat capacity
× change in temperature
energy in J, mass in kg, s.h.c. in J/(kg °C),
change in temperature in °C
b energy = mass × specific latent heat
energy in J, mass in kg, specific latent
heat in J/kg
© Cambridge University Press 2014 IGCSE Physics
increases.
[1]
b
Definition
lower
fixed point
melting point
of pure ice
upper
fixed point
boiling point of
pure water
[1]
Value
0 °C [1]
100 °C
c (for example) the resistance of a
resistor or thermistor
8 a internal energy
b the steel block
It takes more energy to raise the
temperature of the steel block by a
certain amount than that of the
copper block.
9 a the thermocouple thermometer
[1]
[1]
[1]
[1]
[1]
b 100 °C
This is a fixed point on the Celsius scale.
[1]
[1]
c the liquid-in-glass thermometer
It can measure to 0.5 °C (or better);
the other measures to the nearest 1 °C.
[1]
d The properties of the two materials
used in the thermometers do not
vary linearly with temperature.
The voltage of the thermocouple
does not increase at a steady rate as
the temperature goes up.
10 a the final temperature of the block
the mass of the block
[1]
[1]
[1]
[1]
[1]
b If poorly insulated, some energy
will be lost.
[1]
c too high (because the heater will have
to supply more energy to make the
temperature rise by 1 °C)
[1]
Answers to end-of-chapter questions: Chapter 10
1
11 a 0 and 100 (°C)
[1]
b i expands
[1]
ii moves along the tube/up/to the right
stops at/near 100 mark
c arrow slightly to left of −10 mark
[1]
[1]
[1]
b i Q = mcθ
= 100.6 − 12.0 = 88.6
= 0.80 × 3900 × 88.6
= 276 432 J
ii Q = Wt so t = 276 432
620
= 446 s
[1]
[1]
[1]
[1]
[1]
[1]
12 a i electrical method – 3 marks for all 6 points
(deduct 1 mark for each point omitted)
lagged container + lid
liquid (allow water)
heater in liquid
heater connected to electrical supply
voltmeter and ammeter appropriately
connected
thermometer
[3]
or mixtures method – 3 marks for all 6 points
(deduct 1 mark for each point omitted)
lagged container
liquid
hot solid/hot liquid
means of heating hot solid/liquid (seen or
stated)
means of weighing hot solid/liquid/use of
known mass (seen or stated)
thermometer
[3]
ii electrical method – 3 marks for all 5 points
(deduct 1 mark for each point omitted)
initial and final temperatures of liquid or
temperature rise
voltmeter reading
ammeter reading
heating time
mass of liquid
[3]
or mixtures method – 3 marks for all 5 points
(deduct 1 mark for each point omitted)
initial and final temperatures of liquid or
temperature rise
initial and final temperatures of added solid/
liquid or temperature drop
mass of added solid/liquid
mass of liquid
s.h.c. of added solid/liquid
[3]
© Cambridge University Press 2014 IGCSE Physics
Answers to end-of-chapter questions: Chapter 10
2