C10 and C13 Revision

What is the process by which heat is transferred from the Sun to the Earth?

• conduction

• convection

• radiation

• nuclear fusion

The outer surface of an electric kettle is shiny and silvery because shiny, silvery surfaces are .................. .......................... of infrared radiation.

Wollen clothes help to keep us warm because

• conduction and convection are prevented.

• wool is a material that traps heat.

• wool traps air which is a poor conductor of thermal energy.

• radiation is prevented.

Order the process of thermal transfer by convection in an electric kettle.

• Convection current is set up, heating the entire kettle of water.

• Water near the heating coil is heated, gains heat, expands, becomes less dense and rise.

• Cooler water gets heated by heating coil.

• Warmer, less dense water displace cooler, denser water downwards to be heated by heating coil.

Which cup is the best to keep cold drinks cold?

• black, dull cup

• black, shiny cup

• white, dull cup

• white, shiny cup

Which cup is best for keeping hot drinks hot?

• black, dull cup

• black, shiny cup

• white, dull cup

• white, shiny cup

Select the process(es) that cannot occur in a vacuum.

• conduction

• convection

• radiation

Which makes use of the chemical effecting of an electric current?

• heating coil in kettle

• electromagnet

• electroplating

• electrolysis

Overloading of the power sockets may lead to

• wires becoming frayed

• electrical fires

• lower electrical bills

• not enough current flowing in appliance

which safety feature melts when a large current flows through it and needs to be replaced after each use?

• fuse

• circuit breaker

• earth wire

• plastic tubing