Chapter 2 Practice Paper: Heat Transfer — question paper

Section A: Multiple-choice questions[10 marks]

Answer all questions. For each question, write the letter (A, B, C or D) of the correct answer in the brackets provided.

1. 1

   A temperature recorded in the SI unit is measured in

   1. Akelvin.
   2. Bdegrees Celsius only.
   3. Cjoules.
   4. Dmetres.
   ( )
2. 2

   A metal wok is on a stove. The bare handle becomes too hot to hold. Heat reached the handle mainly by

   1. Aconvection of the solid metal.
   2. Bradiation through a vacuum inside the handle.
   3. Cconduction.
   4. Dthe handle gaining mass.
   ( )
3. 3

   Warm air above a room heater rises, and cooler air moves in to take its place. This kind of flow can happen in

   1. Aa vacuum.
   2. Bliquids and gases.
   3. Conly a metal block.
   4. Donly a dull black solid.
   ( )
4. 4

   A satellite is warmed by the Sun while it orbits in empty space. The energy reaches the satellite mainly by

   1. Aconduction through air particles that fill space.
   2. Bconvection currents in space.
   3. Ca change of mass.
   4. Dradiation.
   ( )
5. 5

   Which surface emits infrared radiation fastest?

   1. Adull black
   2. Bshiny white
   3. Cshiny silver
   4. Da mirror
   ( )
6. 6

   In a beaker of water heated at the bottom, the warmer water rises because it is

   1. Amore dense.
   2. Ba solid.
   3. Cless dense.
   4. Dlosing its mass.
   ( )
7. 7

   A metal courtyard gate is hung with a small gap at the latch. The gap lets the gate

   1. Alose mass on a hot afternoon.
   2. Bconduct electricity into the ground.
   3. Cradiate across a vacuum.
   4. Dexpand on a hot day without jamming shut.
   ( )
8. 8

   A polystyrene box keeps a block of ice from melting quickly mainly because

   1. Apolystyrene is a metal.
   2. Bair trapped in the foam is a poor conductor.
   3. Cthe box is a perfect vacuum.
   4. Dthe box stops every ray from the Sun.
   ( )
9. 9

   The empty gap in the wall of a vacuum flask reduces heat loss by

   1. Aconduction and convection.
   2. Bradiation only, and nothing else.
   3. Cincreasing the mass of the drink.
   4. Dmaking the drink boil.
   ( )
10. 10

    Aluminium foil wrapped around a hot takeaway box cuts heat loss mainly by

    1. Aconvection of a solid.
    2. Bconduction through the vacuum.
    3. Creflecting radiation.
    4. Dincreasing the temperature of the room.
    ( )

Section B: Structured questions[20 marks]

Answer all questions in the spaces provided. Show your working for calculations.

1. 1

   A beaker of water is heated from below.

   1. (a)

      Name the process that carries heat through the water.

      [1]
   2. (b)

      Explain why the warmer water rises.

      [2]
   3. (c)

      Explain why the same circulating current cannot happen inside a solid metal block.

      [2]
2. 2

   Two identical cans of hot water cool in the same room. Can P is dull black. Can Q is shiny silver.

   1. (a)

      State which can cools faster.

      [1]
   2. (b)

      Explain your choice using radiation.

      [2]
   3. (c)

      An astronaut’s glove is warmed by sunlight outside the spacecraft. Explain how that energy crosses the empty gap.

      [2]
3. 3

   A steel ruler has a mass of 30 g and a volume of 4.0 cm³ while it is cool. After an hour on a hot radiator its mass is unchanged and its volume is 5.0 cm³.

   1. (a)

      State the mass of the ruler after the hour on the radiator.

      mass =g[1]
   2. (b)

      Calculate the density of the cool ruler.

      density =g/cm³[2]
   3. (c)

      Calculate the density of the hot ruler, and state whether it has risen or fallen.

      density =g/cm³[2]
4. 4

   A vacuum flask has a vacuum between shiny walls. A student also wears a woollen jumper.

   1. (a)

      State which two processes the vacuum reduces.

      [2]
   2. (b)

      Explain how the shiny walls reduce heat transfer.

      [2]
   3. (c)

      The same student wraps a cold drink in bubble wrap. State why the air in the bubbles slows heat gain from the warm room.

      [1]