energy transfers in a system (topic 1)

Question 1

some of the energy released by the burning gas is wasted, what happens to this wasted energy (2)

Answer 1

• wasted energy is transferred to surrounding air
• and is converted to (heat energy)

Question 2

give two reasons for taking repeat readings in an investigation

Answer 2

• calculate a mean
• spot anomalies
• reduce the effect of random errors

Question 3

Answer 3

• as speed increases, the efficiency increases
• (but) graph appears to reach a limit

Question 4

Answer 4

as a source of thermal radiation

Question 5

give one advantage of using a temperature sensor and data logger instead of a glass thermometer to measure temperature

Answer 5

• greater sensitivity / precision
• could link to a computer for (automatic) data analysis
• could take more frequent readings
• reduces instrument reading error

Question 6

explain why the insulation recommended by the student (plastic foam and aluminium foil) will reduce the heat transfer from the Sun to the glacier (2)

Answer 6

• (aluminium) foil is a poor absorber of thermal radiation
• or (aluminium) foil is a (good) reflector of thermal radiation
• (plastic) foam traps air which is a (good) insulator

Question 7

explain, in terms of particles, how heat is transferred through the glass wall of a
boiling tube (2)

Answer 7

• particles vibrate faster, with more (kinetic) energy
• energy transferred by collisions with other particles

Question 8

Answer 8

radiation

Question 9

(1)

Answer 9

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

Question 10

to be able to compare the results, it was important to use the same volume of
water in each test, give one other quantity that was the same in each test

Answer 10

• starting temperature (of the water)
  accept thickness of fleece