2. Thermal physics
A section of Physics, 0625
Listing 10 of 1256 questions
shows a stainless-steel saucepan being heated on an electric cooker. The saucepan contains water. State what happens to the water particles as the water temperature increases. The saucepan contains 250 cm3 of water. The specific heat capacity of water is 4200 J / (kg °C). The density of water is 1000 kg / m3. Show that the mass of the water in the saucepan is 0.25 kg. Calculate the energy required to increase the water temperature from 20 °C to 65 °C. energy = The heater supplies enough power to heat the water in 39 s. A student measures the time taken to heat the water as 115 s. Suggest why the actual time taken to heat the water is longer. Assume that the student takes accurate measurements. The stainless-steel saucepan is replaced with an aluminium saucepan of the same mass. It contains the same volume of water. The specific heat capacity of stainless steel is 500 J / (kg °C). The specific heat capacity of aluminium is 890 J / (kg °C). Explain how using an aluminium saucepan will affect the time taken to heat the water.
0625_s24_qp_43
THEORY
2024
Paper 4, Variant 3
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Some water is heated electrically in a glass beaker in an experiment to find the specific heat capacity of water. The temperature of the water is taken at regular intervals. The temperature-time graph for this heating is shown in . time / s temperature / °C Use the graph to find 1. the temperature rise in the first 120 s, 2. the temperature rise in the second 120 s interval. Explain why these values are different. The experiment is repeated in an insulated beaker. This time, the temperature of the water increases from 20 °C to 60 °C in 210 s. The beaker contains 75 g of water. The power of the heater is 60 W. Calculate the specific heat capacity of water. specific heat capacity = In order to measure the temperature during the heating, a thermocouple is used. Draw a labelled diagram of a thermocouple connected to measure temperature.
0625_w06_qp_3
THEORY
2006
Paper 3, Variant 0
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State what is meant by specific heat capacity. Water has a very high specific heat capacity. Suggest why this might be a disadvantage when using water for cooking. illustrates an experiment to measure the specific heat capacity of some metal. boiling water metal heater insulation lid thread water cup thermometer stirrer The piece of metal is heated in boiling water until it has reached the temperature of the water. It is then transferred rapidly to some water in a well-insulated cup. A very sensitive thermometer is used to measure the initial and final temperatures of the water in the cup. specific heat capacity of water = 4200 J / (kg K) The readings from the experiment are as follows. mass of metal = 0.050 kg mass of water in cup = 0.200 kg initial temperature of water in cup = 21.1 °C final temperature of water in cup = 22.9 °C Calculate the temperature rise of the water in the cup and the temperature fall of the piece of metal. temperature rise of water = temperature fall of metal = Calculate the thermal energy gained by the water in the cup. State the equation that you use. thermal energy gained = Assume that only the water gained thermal energy from the piece of metal. Making use of your answers to and , calculate the value of the specific heat capacity of the metal. Give your answer to 3 significant figures. specific heat capacity = Suggest one reason why the experiment might not have given a correct value for the specific heat capacity of the metal.
0625_w09_qp_31
THEORY
2009
Paper 3, Variant 1
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State what is meant by specific heat capacity. Water has a very high specific heat capacity. Suggest why this might be a disadvantage when using water for cooking. illustrates an experiment to measure the specific heat capacity of some metal. boiling water metal heater insulation lid thread water cup thermometer stirrer The piece of metal is heated in boiling water until it has reached the temperature of the water. It is then transferred rapidly to some water in a well-insulated cup. A very sensitive thermometer is used to measure the initial and final temperatures of the water in the cup. specific heat capacity of water = 4200 J / (kg K) The readings from the experiment are as follows. mass of metal = 0.050 kg mass of water in cup = 0.200 kg initial temperature of water in cup = 21.1 °C final temperature of water in cup = 22.9 °C Calculate the temperature rise of the water in the cup and the temperature fall of the piece of metal. temperature rise of water = temperature fall of metal = Calculate the thermal energy gained by the water in the cup. State the equation that you use. thermal energy gained = Assume that only the water gained thermal energy from the piece of metal. Making use of your answers to and , calculate the value of the specific heat capacity of the metal. Give your answer to 3 significant figures. specific heat capacity = Suggest one reason why the experiment might not have given a correct value for the specific heat capacity of the metal.
0625_w09_qp_32
THEORY
2009
Paper 3, Variant 2
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A student in a laboratory uses the apparatus shown in to determine the specific heat capacity of aluminium. to low voltage supply and measuring instruments electrical heater thermometer aluminium block The readings obtained in the experiment are given below. mass of aluminium block = 0.930 kg initial temperature of block = 13.1 °C final temperature of block = 41.3 °C electrical energy supplied = 23 800 J Define specific heat capacity. Use the readings above to calculate the specific heat capacity of aluminium. State the equation you use. specific heat capacity = Because the student knows it is good scientific practice to repeat readings, after a short time he carries out the experiment again, supplying the same quantity of electrical energy. This time the temperature readings are: initial temperature of block = 41.0 °C final temperature of block = 62.1 °C Use these figures to calculate a second value for the specific heat capacity of aluminium. specific heat capacity = The student did not make any mistakes when taking the readings. Suggest why the second value for the specific heat capacity of the aluminium is greater than the first. Suggest two ways of improving the experiment in order to give as accurate a result as possible. 1. 2.
0625_w10_qp_31
THEORY
2010
Paper 3, Variant 1
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Define specific heat capacity. Solar energy is striking the steel deck of a ship. Describe how the colour of the deck affects the absorption of the solar energy. The solar energy strikes the deck at the rate of 1400 W on every square metre. The steel plate of the deck is 0.010 m thick. Steel has a density of 7800 kg / m3 and a specific heat capacity of 450 J / (kg °C). 13% of the solar energy striking the deck is absorbed and the rest is reflected. Using these figures, calculate 1. how many joules of solar energy are absorbed by 1.0 m2 of the deck in 1.0 s, number of joules = 2. the mass of 1.0 m2 of deck, mass = 3. the rate of rise in temperature of the deck, stating the equation you use. rate of rise = °C / s
0625_w10_qp_33
THEORY
2010
Paper 3, Variant 3
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