Density

Tides and wind are two renewable energy resources.

Describe the difference between renewable energy resources and non-renewable energy resources.

Figure 14 shows a new design of tidal turbine to generate electricity using the tides.

Use the Physics Equations Sheet to answer questions 08.2 and 08.3.

Write down the equation which links density (ρ), mass (m) and volume (V).

The mass of seawater passing through the tidal turbine each second is 824 000 kg.

Calculate the volume of seawater passing through the tidal turbine each second.

The speed of the tide or the speed of the wind past a turbine is called the ‘flow speed’.

Figure 15 shows how the power output of a tidal turbine compares with a wind turbine for different flow speeds.

As flow speed increases, power output increases.

Give two other conclusions that can be made using information from Figure 15.

Figure 16 shows the turbines used to obtain the data for Figure 15.

Compare the environmental impacts of the wind turbine and the tidal turbine in Figure 16.

Tides and wind are two renewable energy resources.

Describe the difference between renewable energy resources and non-renewable energy resources.

Figure 1 shows a new design of tidal turbine to generate electricity using the tides.

Use the Physics Equations Sheet to answer questions 01.2 and 01.3.

Write down the equation which links density (ρ), mass (m) and volume (V).

The mass of seawater passing through the tidal turbine each second is 824 000 kg.

Calculate the volume of seawater passing through the tidal turbine each second.

The speed of the tide or the speed of the wind past a turbine is called the ‘flow speed’.

Figure 2 shows how the power output of a tidal turbine compares with a wind turbine for different flow speeds.

As flow speed increases, power output increases.

Give two other conclusions that can be made using information from Figure 2.

Figure 3 shows the turbines used to obtain the data for Figure 2.

Compare the environmental impacts of the wind turbine and the tidal turbine in Figure 3.

Figure 8 shows a measuring cylinder containing some water.

What range of volumes can be measured using the measuring cylinder?

Tick () one box.

A student used the measuring cylinder to measure the volume of a metal ring.

The student tied the metal ring to some very thin string and lowered the ring into the measuring cylinder.

The student could have used thick string instead of thin string.

How would using thick string have affected the measured volume of the metal ring?

Tick () one box.

Table 1 shows the results.

Calculate value X in Table 1.

The student measured the volume of the ring three times.

The results were all the same.

Which of the following describes the student’s results?

Tick () one box.

The student used a balance to measure the mass of the ring.

Figure 9 shows the balance.

The student noticed that the balance had a reading of 0.02 g when there was no object on the balance.

How should the student correct this error after the mass of the ring had been measured?

Tick () one box.

Use the Physics Equations Sheet to answer questions 04.6 and 04.7.

Write down the equation which links density (ρ), mass (m) and volume (V).

A different metal ring has a volume of 0.3 cm³.

The density of this ring is 22 g/cm³.

Calculate the mass of this ring.

Give your answer in grams.

Figure 11 shows a measuring cylinder containing some water, which a student used to measure the volume of a metal ring.

When measuring the volume, the student’s eye was in line with the level of the water.

Which type of error would have been caused if the student’s eye was not in line with the level of the water?

Tick (✓) one box.

The student tied a piece of thick string to the metal ring and lowered the ring into the water.

Suggest one reason why the student should have used thin string instead of thick string.

Table 2 shows the results.

The true volume of the ring was 0.44 cm³.

Even without using the string, the measuring cylinder could not give an accurate value for the volume of the ring.

Give one reason why.

The student used a balance to measure the mass of the ring.

After the ring was removed from the balance, the reading on the balance was 0.02 g.

How could the student use the readings from the balance to determine the correct mass of the ring?

The student determined that the density of the ring was 21 500 kg/m³.

The volume of the ring was 0.44 cm³.

Calculate the mass of the ring.

Use the Physics Equations Sheet.

Give your answer in kg.

Figure 14 shows a rock found by a student on a beach.

To help identify the type of rock, the student took measurements to determine its density.

Describe a method the student could use to determine the density of the rock.

The student determined the density of the rock to be 2.55 ± 0.10 g/cm³.

What are the maximum and minimum values for the density of the rock?

Table 3 gives the density of five different types of rock.

Which two types of rock in Table 3 could be the type of rock the student had?

Tick (✓) one box.

The student only took one set of measurements to determine the density of the rock.

Explain why taking the measurements more than once may improve the accuracy of the density value.

Figure 2 shows a rock found by a student on a beach. To help identify the type of rock, the student took measurements to determine its density.

Describe a method the student could use to determine the density of the rock.

The student determined the density of the rock to be 2.55 ± 0.10 g/cm³.

What are the maximum and minimum values for the density of the rock?

Table 1 gives the density of five different types of rock.

Which two types of rock in Table 1 could be the type of rock the student had? Tick (✓) one box.

The student only took one set of measurements to determine the density of the rock. Explain why taking the measurements more than once may improve the accuracy of the density value.

A student investigated the density of different fruits.

To determine the density of each fruit, the student measured the volume of each fruit.

Figure 3 shows the equipment the student could have used.

Describe a method the student could have used to measure the volume of the lime.

The student measured the volume of each fruit three times and then calculated a mean value.

The three measurements for a grape were

Calculate the mean value.

What are the advantages of taking three measurements and calculating a mean value?

Tick (✓) two boxes.

The mass of an apple was 84.0 g.

The volume of the apple was 120 cm³.

Calculate the density of the apple.

Give your answer in g/cm³.

Use the equation:

Table 1 shows the results.

The student determined the volume of each fruit using a displacement can and a measuring cylinder. What other piece of equipment would the student need to determine the density of each fruit?

Write down the equation which links density (ρ), mass (m) and volume (V).

The mass of the apple was 85 g. The density of the apple was 0.68 g/cm³. Calculate the volume of the apple. Give your answer in cm³.

The student only measured the volume of each fruit once. The volume measurements cannot be used to show that the method to measure volume gives precise readings. Give the reason why.

Figure 14 shows a hydroelectric power station.

Electricity is generated when water from the reservoir flows through the turbines.

Write down the equation which links density (ρ), mass (m) and volume (V).

The reservoir stores 6 500 000 m³ of water.

Calculate the mass of water in the reservoir. Give your answer in standard form.

Write down the equation which links energy transferred (E), power (P) and time (t).

The electrical generators can provide 1.5 × 10⁹ W of power for a maximum of 5 hours. Calculate the maximum energy that can be transferred by the electrical generators.

Figure 15 shows how the UK demand for electricity increases and decreases during one day.

The hydroelectric power station in Figure 14 can provide 1.5 × 10⁹ W of power for a maximum of 5 hours. Give two reasons why this hydroelectric power station is not able to meet the increase in demand shown between 04:00 and 16:00 in Figure 15.

Figure 4 shows a hydroelectric power station.

Electricity is generated when water from the reservoir flows through the turbines.

Write down the equation which links density (ρ), mass (m) and volume (V).

The reservoir stores 6 500 000 m³ of water.

Calculate the mass of water in the reservoir. Give your answer in standard form.

Write down the equation which links energy transferred (E), power (P) and time (t).

The electrical generators can provide 1.5 × 10⁹ W of power for a maximum of 5 hours. Calculate the maximum energy that can be transferred by the electrical generators.

Figure 5 shows how the UK demand for electricity increases and decreases during

The hydroelectric power station in Figure 4 can provide 1.5 × 10⁹ W of power for a maximum of 5 hours. Give two reasons why this hydroelectric power station is not able to meet the increase in demand shown between 04:00 and 16:00 in Figure 5.

Figure 1 shows water being heated. Eventually the water changed into steam.

Complete the sentences. Choose answers from the box. Each answer may be used once, more than once or not at all.

distance between the particles in liquid water.

Figure 2 shows how the temperature of the water varied with time.

What is the name of the process that is taking place between points A and B ? Give a reason for your answer.

A mass of 0.063 kg of water was turned into steam. The specific latent heat of vaporisation of water is 2 260 000 J/kg

Calculate the thermal energy transferred to the water to turn it into steam. Use the equation: thermal energy for a change of state = mass × specific latent heat

The mass of the steam was 0.063 kg The volume of the steam was 0.105 m³

Calculate the density of steam. Use the equation:

Choose the unit from the box.

A student measured the width of a solid metal cube using a digital micrometer.

Figure 11 shows the micrometer.

The resolution of the micrometer is 0.01 mm

The student could have used a metre rule to measure the width of the cube.

Explain how using a metre rule would have affected the accuracy of the student’s measurement of width.

The mass of the metal cube was measured using a top pan balance.

The balance had a zero error.

Explain how the zero error may be corrected after readings had been taken from the balance.

The width of the cube was 18.45 mm. The density of the cube was 8.0 × 10³ kg/m³

Calculate the mass of the cube.

Figure 14 shows a Bunsen burner heating some water in a beaker. Eventually the water changes into steam.

Explain how the internal energy of the water changes as it is heated from 20 °C to 25 °C

How is the particle model used to explain the difference in density between a liquid and a gas?

Tick (✓) one box.

A student measured the mass of boiling water that was turned into steam in five minutes.

Explain how the student could use this information to estimate the power output of the Bunsen burner in watts.

A student wanted to determine the density of a small piece of rock.

Describe how the student could measure the volume of the piece of rock.

The volume of the piece of rock was 18.0 cm³.

The student measured the mass of the piece of rock as 48.6 g.

Calculate the density of the rock in g/cm³.

Use the equation:

Figure 4 shows the densities of different types of rock.

What is the most likely type of rock that the student had?

Tick one box.

Give one source of error that may have occurred when the student measured the volume of the rock.

How would the error you described in question 04.4 affect the measured volume of the rock?

Figure 16 shows a wind turbine.

Figure 16

At a particular wind speed, a volume of 2.3 ×10⁴ m³ of air passes the blades each second.

Calculate the mass of air passing the blades per second.

The power output of the turbine is directly proportional to the kinetic energy of the air passing the blades each second.

Describe the effect on the power output when the wind speed is halved.

At a different wind speed, the wind turbine has a power output of 388 kW.

The mass of air passing the wind turbine each second is 13 800 kg.

Calculate the speed of the air passing the blades each second.

Assume that the process is 100% efficient.