A student investigates whether a matt black can or a shiny silver can is the better emitter of infrared radiation.
The Table shows the student's method and results.
Table
| Can | Volume of water in cm3\text{cm}^{3}cm3 | Lid | Starting temperature in ∘C^{\circ}\text{C}∘C | Temperature after 10 minutes in ∘C^{\circ}\text{C}∘C |
|---|---|---|---|---|
| matt black | 200 | no | 85 | 66 |
| shiny silver | 300 | yes | 75 | 67 |
Calculate the temperature fall of the water in each can.
The student concludes that the matt black surface is the better emitter.
Explain why the results do not allow a valid conclusion to be made.
Both cans are left in the room for several hours. Both cans reach 21 ∘C21\ ^{\circ}\text{C}21 ∘C and then stay at this temperature.
Explain why the temperature of each can stops changing.
The cans are then put in a fridge to cool to 5 ∘C5\ ^{\circ}\text{C}5 ∘C and taken back into the room.
Explain why the matt black can warms up faster than the shiny silver can.
96 exam-style questions on Edexcel GCSE Physics 5.3 Black body radiation, covering 5.3.1 Emission of radiation and temperature, 5.3.2 Radiation balance and constant temperature, and 5.3.3 The temperature of the Earth. Each one has a worked solution and a mark scheme showing where the marks go.