WorksheetsRadiation
Total questions: 15
Worksheet time: 8mins
The radiators on motor cars are painted black because ________.
black surface is more beautiful
a black surface can conduct heat better
a black surface is a good radiator of infra-red rays
it will not get dirtt easily
By which process is thermal energy transferred through a vacuum?
conduction only
convection only
conduction and convection only
radiation only
Which type of surface is the best absorber of infra-red rays?
black and rough
black and smooth
white and rough
white and smooth
Which type of surface is the best radiator of infra-red rays?
black and rough
black and smooth
white and rough
white and smooth
The diagram shows a simple form of solar water heater. Which tubing would give the hottest water from the outlet?
black, plastic
copper, painted black
copper, painted white
white plastic
A slice of bread is placed under a red-hot electric grill to make toast. What is/are the main process/processes by which the energy reach the bread?
By conduction only.
By conduction and convection
By convection and radiation
By radiation only
We feel the intense heat from the Sun when we stand in the open during noon time. How is heat transferred from the Sun to the Earth?
By radiation only.
By conduction and radiation only.
By convection and radiation only.
By conduction, convection and radiation.
A teapot is needed to keep tea hot for a long period of time. Which of the following best explains why teapots are usually made of a shiny metal?
Shiny surfaces are good absorbers of infra-red radiation.
Shiny surfaces are good emitters of infra-red radiation.
Shiny surfaces are poor absorbers of infra-red radiation.
Shiny surfaces are poor emitters of infra-red radiation.
Four different closed vessels contain equal amounts of ice.
Which vessel would take the shortest time for all the ice to melt?
A
B
C
D
A piece of aluminium foil is used to wrap around food to be cooked in an oven. The foil has a shiny side and a dull side. Which side should be on the outside and why?
The dull side should be on the outside because it absorbs heat by radiation faster.
The shiny side should be on the outside because it is a better conductor of heat.
The dull side should be on the outside because it encourages convection current to be set up.
The shiny side should be on the outside because it is a better absorber of heat by radiation.
The diagram shows a vacuum flask.
The main reason for the vacuum is to reduce heat transfer by
conduction and convection.
conduction only.
radiation only.
convection only.
The following cans are filled with hot water. Which one of the following cans will lose heat most quickly?
A
B
C
D
Two cars, one painted dull black and the other a shiny white, were left in the sun. Which car will be heated up faster? When the two cars had reached the same temperature they were driven into the shade. Now, which car will cool down faster?
A
B
C
D
A few soccer boys were trapped in a cave in Thailand in 2018. One of the things that rescuers did was to wrap a thin plastic blanket, with a shiny metallic surface, around the boys. What type of thermal energy transfer (heat loss) is the shiny surface intended to reduce?
conduction
convection
radiation
conduction and convection
Which of the following will increase the rate of heat transfer?
1 Increase the temperature difference.
2 Paint the surface black.
3 Increase the surface area.
1 and 2 only
1 and 3 only
2 and 3 only
1, 2 and 3
