Density (Cambridge O Level Physics)

Exam Questions

2 hours28 questions
1a
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1 mark

Fig. 1.1 shows a set of masses made from the same material.

2019-feb-mar-q1

Fig. 1.1

Identify the quantity that is the same for all the masses.

Tick one box.

square density
square volume
square weight
1b
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1 mark

The largest mass is 2.5 kg.

State the number of grams in 2.5 kg.

 
 

2.5 kg = ...................................................... g 

1c
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4 marks

The three largest masses are 2.5 kg, 1.0 kg and 0.5 kg.

Calculate the combined weight of these three masses. Include the unit.

 
 

weight = ......................................................... 

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2a
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3 marks

Fig. 2.1 shows a wooden raft. The raft is made from 8 logs.
The logs are all of the same type of wood.

q2a

The average mass of each log is 65.0kg.
Calculate the total weight of the raft.

total weight of the raft = ....................................................... N 

2b
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4 marks

(i)

The mass of one of the logs is 66.0kg. It is 3.0m long and has a cross sectional area of 0.040m2.

Calculate the density of the wood in the log.

density = ............................................... kg / m3 [3]

(i)

Explain why the log in (b)(i) floats on water.

[1]

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3a
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1 mark

Identify the unit that is used for mass.

Tick one box.

square kg
square N
square m3
3b
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4 marks

A student is asked to write definitions for mass and weight.              

For each of their answers insert the missing word, selected from the list below.

force   gravity   kilogram   mass   matter   newton   rest


(i)1-3-3b-e-mass-question-weight-question-1
[2]
(ii)1-3-3b-e-mass-question-weight-question-2
[2]
3c
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3 marks

A student needs to determine the density of a sample of oil.

They measure 0.001 m3 of oil and find it has a mass of 0.75 kg.

            
(i)
State the equipment the student uses to find the mass of oil.
[1]
           
(ii)
Calculate the density of the oil.
[2]
3d
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2 marks

The oil in part (c) is poured into a beaker of water.

Assuming that the liquids do not mix, explain which liquid floats.

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4a
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4 marks

Fig. 1.1 shows laboratory equipment used to find the density of an irregularly shaped solid.

1-3-5a-e-measuring-cylinder-and-scales

Fig. 1.1

For each piece of equipment add a label stating the name and the quantity measured.

4b
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4 marks

Explain how a student can find the volume of a piece of modelling clay of irregular shape using only the equipment in part (a)

4c
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1 mark

The volume of the modelling clay is found to be 64 cm3.

State the volume in m3.

4d
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4 marks

The mass of the modelling clay is 60 g.

                           
(i)
Determine the mass in kg.
[1]
(ii)
Calculate the density of the modelling clay, stating your answer in terms of S.I. units.
[3]

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1a
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3 marks

Fig. 1.1 shows a coil of wire.

cie-2020-31-1

A student measures the length of the coil using a ruler. His measurement is 3.8 cm.

There are 20 turns of wire in the coil. The student uses his measurement to calculate the average thickness of the wire.

 
(i)
Show that the average thickness of the wire is about 0.2 cm.
 
 
average thickness of wire = .................................................. cm [2] 
  
(ii)
The student’s measurement of 3.8cm is inaccurate.
 
Suggest one reason why the measurement is inaccurate.
[1]
1b
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3 marks

The volume of the wire in the coil is 16.6 cm3 and its mass is 148 g.

 

Calculate the density of the metal used for the wire in the coil.

 
 
density = ............................................. g/cm3 
1c
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4 marks

The student has a measuring cylinder and a beaker of water, as shown in Fig. 1.2.

 
cie-2020-31-2
 
Describe how the student can determine the volume of the coil by using the equipment shown in Fig. 1.2.

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2a
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6 marks

A 250 cm3 beaker containing some liquid is shown in Fig. 2.1.

q2

(i)
A student has a measuring cylinder and a balance.

Describe an experiment to determine the density of the liquid.
[5]
 
(ii)
Suggest the unit of density used by the student.
[1]

2b
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4 marks

Fig. 2.2 shows a block of polythene.

 
q2-b
 
(i)
Polythene floats in water. Explain why polythene floats.
[1]
(ii)

The weight of the polythene block is 0.84 N.

Calculate the mass of the block.

mass = ..................................................... kg [3]

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3a
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4 marks

A student has an irregularly shaped piece of metal, a beaker of water and a measuring cylinder, as shown in Fig. 2.1.

screenshot-2022-10-20-at-15-15-45

Describe how the student can accurately determine the volume of the piece of metal using the equipment provided.

3b
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5 marks

The student measures the mass of the piece of metal. Its mass is 146 g.

 
(i)
State the name of the instrument used to measure the mass.

[1]

    

(ii)
The volume of the piece of metal is 20 cm3.
Calculate the density of the metal. State the unit.
    
   
density = ......................................................  [4]

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4a
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1 mark

Explain, in terms of their molecules, why the density of water is greater than that of oil.

4b
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1 mark

State the difference between mass and weight.

4c
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3 marks

The mass of a bucket is 1.2 kg.

When the bucket is filled with oil the total mass is found to be 14.1 kg.

Calculate the weight of the oil.

 

weight of oil =....................................................

 

4d
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2 marks

The volume of the oil in the bucket is 0.0163 m3.

    

Calculate the density of the oil.

density = ....................................................

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1
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3 marks

Fig. 1.1 shows a plastic water barrel. The barrel is full of water.

screenshot-2022-10-12-at-12-52-31

 

The water barrel contains 0.050 m3 of pure water. The density of pure water is 1000 kg/m3.


Calculate the mass of pure water in the barrel.

 

mass of water = ...................................................... kg 

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2a
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6 marks

A student has a metal object.


(i)
The student measures the mass of the object.

State the name of the equipment used to measure the mass.
[1]
 
(ii)
The mass of the metal object is 1260 g. The volume of the metal is 150 cm3.
 
Calculate the density of the metal. Include the unit.
     
 
density = .............................................. [4]
 
(iii)
The mass of the metal object is given in grams. State the mass in kg.
   
 
   
mass = .................................................... kg [1]
2b
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4 marks

A vase is placed on a table. Forces X and Y act on the vase, as shown in Fig. 1.1.
 vase
The mass of the vase is 0.25 kg. The vase is not moving.

 
Calculate the value of force X and the value of force Y.

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3a
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5 marks

A group of students are asked to find the volume of their Physics Laboratory.

Fig. 1.1 is a top view of the room and shows the measurements of each wall.

1-3-q4a-h--room-floor-plan
Fig 1.1
                            

The lab has a ceiling which is at constant height, found to be 3.5 m.

            
(i)
State an instrument that would be suitable to make these measurements.
[1]
(ii)
Describe a method the students could use to reduce errors in their measurements.
[2]
(iii)
Explain how they should ensure the results are reliable.
[2]

3b
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4 marks

Calculate the volume of air in the room.

3c
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3 marks

The density of the air is 1.2 kg / m3. Calculate the mass of air in the room.

3d
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6 marks

Describe a method the students could use to find the density of air. You do not need to include details of the calculation.

  

The students have been provided with the following equipment:

  
Balloon
Large measuring cylinder
Bucket
Water
Digital scales

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4a
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3 marks

In a car boot sale a student sees what the seller says is a model soldier made from copper. The student buys the model, hoping that it is really made from gold.

At Science Club the student is allowed to investigate their theory.

Describe how the volume of the model could be measured.

You may use a diagram if you wish.

4b
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4 marks

The student used a force meter for the next stage of their investigation.

                      
(i)
Describe how the force meter is used to find mass.
[3]
 
(ii)
Explain how the student reduces errors in their reading.
[1]
4c
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4 marks

The mass of the model is 625 g and the volume is 72 cm3.

The densities of various metals commonly used in model-making are:

  brass   8.73 g/cm3 
  copper 9.0 g/cm3 
  gold 19 g/cm3 
  lead 11 g/cm3 

By comparison with values in the data table, discuss the student's findings and whether the model is made from either copper or gold.

4d
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3 marks

Another student decides to find the density of a table-tennis ball using the same apparatus.

 

Discuss a change the student have to make before making their measurements.

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