p2 energy transfer by heating

The best emitters of infrared radiation have ......................................................................... surfaces. The worst emitters of infrared radiation have ......................................................................... surfaces.

dark matt,light shiny

B A C

Apart from material of the can, mass of water and starting temperature, suggest three control variables for the student’s investigation.

same area,same surface underneath cans • same position in the room

fox a,smaller ears,thicker fur,these minimise energy transfer

After 1 hour, the temperature of the room has become constant, even though the heater is still switched on.

the room is losing heat,at the same rate as the heater supplies it

plastic is a poor conductor,plastic cap reduces energy transfer by conduction. glass is a poor conductor so reducing energy transfer by conduction glass reduces energy transfer by conduction.vacuum: both conduction and convection require a medium.vacuum stops energy transfer by conduction.silvered surfaces are poor emitters of infrared radiation

(the ears have a) small surface area,so reducing energy transferred from the fox

conduction,convection

70,70-55=15,c biggest drop in temperature during a given time

starting at 70 °C and below graph for C,because 20 °C is room temperature

0.2x4200x8=6720

the fastest particles have enough energy ,to escape from the surface of the water therefore the mean energy of the remaining particles decreases the lower the mean energy of particles the lower the temperature of the water

) Why did she use an infra red lamp?

as a source of thermal radiation,same room temperature

greater sensitivity

Why did the student use a boiling tube with no insulation? ................................................................................................................... ................................................................................................................... From her results, what should she recommend is used to insulate the glacier? ................................................................................................................... (

acts as a control,(plastic) foam and aluminium foil,

Explain why the insulation recommended by the student will reduce the heat transfer from the Sun to the glacier.

aluminium foil is a poor absorber of thermal radiation,plastic foam traps air which is a good insulator

particles vibrate with more ke,energy transferred by collisions with other particles

radiation,traps small pockets of air

bigger temperature difference between the water and surroundings at the start than at the end,starting temperature (of the water)

18 degrees celcius, M smallest temperature drop (after 20 mins)

initial temperature was a control variable

Which metal had the highest thermal conductivity? Give a reason for your answer. Metal: ______________________________________________________ Reason: _________________________________________

copper,greater change in mass than the other metals

variation in initial mass of ice cube

E = m × 2100 × 15 E = m × 334000,5848 = 31500 m + 334000 m,5848/365500,m = 0.016 (kg)

When the kettle was switched on the temperature of the water did not immediately start to increase. Suggest one reason w

the heating element of the kettle takes time to heat up

155000 = m × 4200 × 78, 155000/4200x78,m = 0.47 (kg)

E = 2530 × 14,E = 35 420J,35 420 = m × 4200 × 7,35420/294000=0.12