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Transfer of heat
6 Class 9 Physics questions with answers and explanations.
Printable worksheet with answer key
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Heat travels through a solid mainly by:
- 1 Convection
- 2 Conduction
- 3 Radiation
- 4 Evaporation
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Correct answer: Conduction
In solids heat is passed from particle to particle by conduction.
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Heat reaches the Earth from the Sun by:
- 1 Radiation
- 2 Reflection only
- 3 Convection
- 4 Conduction
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Correct answer: Radiation
Radiation does not need a medium, so it can cross empty space.
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Convection takes place in:
- 1 Fluids
- 2 Solids only
- 3 A vacuum
- 4 Metals only
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Correct answer: Fluids
Convection needs the bulk movement of a liquid or gas.
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Which of these is a good conductor of heat?
- 1 Air
- 2 Wood
- 3 Copper
- 4 Plastic
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Correct answer: Copper
Metals such as copper conduct heat well. Wood, plastic and air are poor conductors.
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A vacuum flask keeps liquids hot mainly because it reduces:
- 1 Conduction, convection and radiation
- 2 Only radiation
- 3 Only conduction
- 4 Only the liquid's mass
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Correct answer: Conduction, convection and radiation
The vacuum stops conduction and convection, and the shiny walls reduce radiation.
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Which colour of surface is the best absorber of heat radiation?
- 1 Dull black
- 2 Silver
- 3 Shiny yellow
- 4 White
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Correct answer: Dull black
Dull black surfaces absorb and emit radiation best.