Heat transfer: conduction, convection and radiationIB MYP Physics: Flashcards

Exam questions on Heat transfer: conduction, convection and radiation

1. A chef in Istanbul cooks soup on a hob using a stainless steel pan with a plastic handle. The base of the pan heats up very quickly, but the plastic handle stays cool enough to hold.
   Explain why the metal base heats up quickly but the plastic handle stays cool.2 marks
2. A radiator is fixed to one wall of a classroom in Oslo, close to the floor. When it is switched on, the whole room soon warms up, even the corner furthest from the radiator.
   Explain how the energy from the radiator spreads through the whole room.2 marks
3. A student investigates how the surface of a can affects how quickly it cools. She uses three identical metal cans with lids: one painted dull black, one painted white and one with a shiny silver surface. She fills each can with 200 cm³ of water at 80 °C and leaves them in the same room at 20 °C. After 10 minutes the water temperatures are 55 °C (dull black can), 63 °C (white can) and 68 °C (shiny silver can). Her hypothesis was that dull black surfaces lose energy fastest.
   Identify the independent variable and the dependent variable in the investigation, and state one control variable.3 marks