IGCSE Physics | Practice Test | 25 Questions
Write down the definition of density.
Write down the equation for density. Name each symbol and state its unit.
Write down the density equation rearranged to find:
(a) mass
(b) volume
State the density of water in g/cm³.
Name the laboratory instrument used to measure the volume of a liquid.
Explain in one or two sentences what is meant by volume by displacement.
State the density condition for an object to float in a liquid.
State the density condition for an object to sink in a liquid.
When using the displacement method to find the volume of an irregularly shaped solid, why must the solid sink completely to the bottom of the measuring cylinder?
State the rule for deciding which of two immiscible (non-mixing) liquids will form the top layer in a container. Supplement
A rectangular metal block has length 10 cm, width 5 cm and height 2 cm. Its mass is 200 g. Calculate the density of the block.
A measuring cylinder contains 100 cm³ of a liquid. The mass of the liquid is 92 g. Calculate the density of the liquid.
A piece of iron has density 7.8 g/cm³ and volume 10 cm³. Calculate the mass of the iron.
A material has density 2.5 g/cm³. A sample of this material has mass 100 g. Calculate the volume of the sample.
A rock is lowered into a measuring cylinder of water. The water level rises from 30 cm³ to 50 cm³. The rock has mass 96 g. Calculate the density of the rock.
A student pours a liquid into a measuring cylinder. The empty cylinder has mass 50 g. After adding liquid, the volume reads 40 cm³ and the total mass is 86 g.
(a) Calculate the mass of the liquid.
(b) Calculate the density of the liquid.
(c) The student adds more of the same liquid until the total volume reaches 80 cm³. Calculate the mass of this larger volume of liquid.
Three objects are placed in water (density 1.0 g/cm³). Object A has density 0.7 g/cm³, Object B has density 1.3 g/cm³ and Object C has density 1.0 g/cm³. For each object, state what happens when it is placed in water and explain why.
A metal block has length 8 cm, width 5 cm and height 2 cm. Its mass is 400 g.
(a) Calculate the volume of the block.
(b) Calculate the density of the block.
(c) Will the block float or sink in water (density 1.0 g/cm³)? Explain your answer.
A stone has mass 0.2 kg and volume 80 cm³. Calculate the density of the stone in g/cm³. Convert the mass to grams first.
A hollow wooden ball has density 0.65 g/cm³. A solid glass marble has density 2.5 g/cm³. Both are placed in water (density 1.0 g/cm³). Using the density data, explain what happens to each object.
A student investigates the density of an irregularly shaped stone.
(a) Describe how to use a measuring cylinder and water to find the volume of the stone.
(b) The student records: initial water level = 25 cm³, final water level = 55 cm³. Calculate the volume of the stone.
(c) The stone has mass 90 g. Calculate the density of the stone.
(d) Will the stone float or sink in water (density 1.0 g/cm³)? Justify your answer using your result from (c).
A scientist has a liquid with density 1.2 g/cm³. A sample of the liquid has mass 120 g.
(a) Calculate the volume of the liquid sample.
(b) The scientist needs 300 cm³ of the same liquid. Calculate the mass of this volume.
(c) Explain why the density does not need to be re-measured to answer part (b).
The five objects below are placed in water (density 1.0 g/cm³):
- Cork — density 0.24 g/cm³
- Ice — density 0.92 g/cm³
- Pine wood — density 0.50 g/cm³
- Rubber — density 1.2 g/cm³
- Aluminium — density 2.7 g/cm³
(a) List all the objects that will float in water.
(b) List all the objects that will sink in water.
(c) Ice is made from water. Using the density data, explain why ice floats on liquid water (density 1.0 g/cm³).
Supplement Three liquids are placed in a container. They do not mix with each other:
- Liquid X — density 1.6 g/cm³
- Liquid Y — density 0.7 g/cm³
- Liquid Z — density 1.1 g/cm³
(a) Which liquid forms the top layer? Explain your answer.
(b) Which liquid forms the bottom layer? Explain your answer.
(c) A student says: “If I pour a large amount of Liquid Z into the container, its weight will push Liquid X out of the way, and Liquid X will end up at the top.” Is the student correct? Explain your answer.
A student is given an unknown metal sample. They use the displacement method to find its density.
(a) Describe the steps the student should follow to find the volume of the metal sample using a measuring cylinder of water.
(b) The student records the following results:
- Mass of metal sample = 237 g
- Water level before adding metal = 50 cm³
- Water level after adding metal = 80 cm³
Calculate the volume of the metal sample and its density. Show all working.
(c) Will the metal sample float or sink in water (density 1.0 g/cm³)? Explain using your answer from (b).
(d) State one source of error when reading the volume from a measuring cylinder. Explain how this error could affect the calculated density.
