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WorksheetsMoment and Heat
Total questions: 20
Worksheet time: 15mins
If a nut and bolt are difficult to undo, it may be easier to turn the nut by using a longer spanner. This is because the longer spanner gives ?
a larger turning moment.
a smaller turning moment.
less friction.
more friction
What is the moment of the force F about the pivot P?
F x h
F x l
F x d
F x s
What is the unit of moment of force?
Nm-2
Nm-1
Nm
Nm/s
A man uses clay to make a pot. He wants the pot to be as stable as possible when placed on a flat surface. Which two features of the pot must the man consider?
the density of the clay and the area of the base
the density of the clay and the height of the centre of gravity
the weight and the height of the centre of gravity
the area of the base and the height of the centre of gravity
which of the following is not include as simple machine?
Lever
Wheel and axle
Fulcrum
Pulley
How does heat transfer through a vacuum take place?
by conduction, convection and radiation
by conduction only
by radiation only
by convection only
Density changes are responsible for which method of thermal energy transfer?
conduction only
convection only
radiation only
conduction, convection, and radiation
A slice of bread is placed under a red-hot electric grill to make toast. How does heat energy reach the bread?
conduction only
convection only
radiation only
convection, conduction, and radiation
A solid bar is heated at one end. How is thermal energy transferred to the other end of the bar?
Heated molecules move along the bar, carrying energy to the other end.
Heated molecules move along the bar, giving energy to others along the bar
Heated molecules stay completely still, but give energy to other molecules.
Heated molecules vibrate more rapidly and pass energy to other molecules.
The tubes inside solar heating panels use the Sun’s radiation to warm water. Why are the tubes painted black?
Black surfaces absorb radiation well.
Black surfaces conduct heat well.
Black surfaces emit radiation well.
Black surfaces reflect radiation well.
Four wet towels are hung out to dry as shown. Which towel dries most quickly?
A
B
C
D
The diagram shows a cooling unit in a refrigerator. Why is the cooling unit placed at the top?
Cold air falls and warm air is displaced upwards.
Cold air is a bad conductor so heat is not conducted into the refrigerator.
Cold air is a good conductor so heat is conducted out of the refrigerator.
Cold air remains at the top and so prevents convection.
Which row gives the correct name for each change of state shown?
A
B
C
D
A liquid is heated and it expands. How does this lead to the formation of a convection current?
The mass of the heated liquid molecules decreases.
The mass of the heated liquid molecules increases.
The density of the heated liquid decreases.
The density of the heated liquid increases.
A pure liquid is left in an open beaker and some of the liquid molecules escape by evaporation. Which statement about this process is correct?
None of the escaping molecules return to the liquid.
The escaping molecules are generally the more energetic ones.
The rate of escape of the molecules can be increased by increasing the depth of the liquid in the beaker.
The temperature of the remaining liquid is unaffected by the escape of the molecules.
One end of a shiny metal rod is heated and the other end quickly gets hot. Which statement describes why the other end quickly gets hot?
Metals are good thermal conductors.
Metals are poor thermal conductors.
Shiny surfaces are good emitters of infra-red radiation.
Shiny surfaces are poor emitters of infra-red radiation
Which statement about convection is not correct?
It enables water in a pan on a cooker to get evenly heated.
It occurs because the density of a fluid decreases when it is heated
It happens in liquids and gases.
It means that heat rises.
Four campers are warming their food on a fire. They use different rods, each of the same dimensions, to hold their food near the fire. Which material is the best choice to prevent their hands from getting too hot?
alumunium
wood
copper
steel
Two methods by which thermal energy can be transferred are conduction and radiation. Which statement is correct?
Conduction involves density changes in fluids.
Conduction only occurs in solids.
Radiation cannot occur in a vacuum.
Radiation involves electromagnetic waves.
In an experiment to measure specific heat capacity, a block of aluminium is heated and its rise in temperature is measured. The amount of energy gained by the block is E. The mass of the block is m. The rise in temperature of the block is ∆T. Which expression gives the specific heat capacity of aluminium?
E x∆Tm
Em x ∆T
m x ∆TE
mE x ∆T
