Grade 10 Physical Sciences · Electricity and Magnetism

Read a graph of results

Read values from a graph or table of results, or calculate a gradient (finding resistance from the gradient of a V-I graph).

past paper questions use it: 13 past paper questions use it
videos: 3 videos

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A Level Practical Endorsement - Calculating Gradients and InterceptsPhysics Online

ECZ: Plotting a Graph of Voltage against Current and finding Resistance from the graph ! PhysicsTeacher Sikazwe Bsc

How to Find Gradient from a Graph in Physics - Intro to Graphs Part 3 | Junior RobertsJunior Roberts

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Question 8.2 · May/June 2024 · Paper 2 · National (DBE) · 2 marks

The relationship between the concentration of the electrolyte and the cell potential is investigated using the following electrochemical cell represented by the cell notation:

Aℓ(s) |

A ℓ^{3 +}

(aq) ||

M^{2 +}

(aq) | M(s)

The concentration of

M^{2 +}

is changed and the corresponding emf is measured. The concentration of

A ℓ^{3 +}

(aq) and the temperature are at standard conditions. The graph below shows the results of this investigation. Diagram for this question

8.2 Determine the concentration of

M^{2 +}

(aq) that will produce an emf of

1, 87

V.(2)

Work it out on paper first. Then mark yourself with the official memo, one tick at a time.

More past paper questions: read a graph of results

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3. Question 4.2.1 · November 2025 · Paper 1 · National (DBE) · 3 marks
Cricketers at an academy conduct an experiment to determine the relationship between the contact time and the final momentum of a ball for a constant average net force.

A cricket ball of mass $150$ g is thrown horizontally with a certain initial velocity and is struck by a bat so that the ball moves in the opposite direction, as shown in the diagram below. The average net force acting on the ball is horizontal.

The experiment is repeated using the same ball. The average net force and the initial velocity of the ball are kept constant. The contact time between the bat and the ball is changed EACH time. The results obtained are shown in the sketch graph below.
4.2 Calculate the:
4.2.1 Average net force acting on the ball(3)
Show the memo (3 ticks)Memo
1. ✓
  METHOD 1: Change in final momentum (numerator)Gradient $= F_{n e t} = \frac{Δ p _{f}}{Δ ( Δ t )}$
  $= \frac{4 , 5 - 0}{\dots}$
  1 mark · Read a graph of results
2. ✓
  METHOD 1: Change in contact time (denominator) $F_{n e t} = \frac{4 , 5 - 0}{0 , 03 - 0 , 01} = 225$ N
  1 mark · Read a graph of results
3. ✓
  METHOD 1: Answer with direction $F_{n e t} = 225$ N to the right / opposite to the original direction of the ball
  1 mark · Read a graph of results
4. Question 5.3.1 · November 2022 · Paper 2 · National (DBE) · 2 marks
Three experiments, A, B and C, are carried out to investigate some of the factors that affect the rate of decomposition of hydrogen peroxide, $H_{2} O_{2} (ℓ)$ .

The balanced equation for the reaction is:

$2 H_{2} O_{2} (ℓ) \to 2 H_{2} O (ℓ) + O_{2} (g)$

Identical samples of hydrogen peroxide are used in each experiment.

The conditions used in each experiment are summarised in the table below.
5.3 The volume of oxygen gas, $O_{2}$ (g), produced in experiment B during the first $3, 6$ s is collected in a syringe, as shown below.
5.3.1 Write down the volume of $O_{2}$ (g) collected in the syringe.(2)
Show the memo (1 tick)Memo
1. ✓
  Syringe reading $560$ (cm $^{3}$ ) / $0, 56$ dm $^{3}$
  2 marks · Read a graph of results
5. Question 7.2.2 · May/June 2022 · Paper 1 · National (DBE) · 4 marks
7.2 P is a variable point in the electric field of charged sphere A and r is the distance between point P and the centre of sphere A. See the diagram below.

A learner determines the magnitude of the electric field (E) at point P for different values of r.

Sphere A is then replaced by another sphere, B, of a different charge. Another set of results are obtained.

The graphs below are obtained from the results for sphere A and sphere B. $E_{A}$ is the magnitude of the electric field at a distance of $0, 04$ m from the centre of charged sphere A.

Use the graphs to answer the following questions.
7.2.2 Calculate $E_{A}$ if the numerical value of the gradient of the graph for sphere A is $680$ .(4)
Show the memo (4 ticks)Memo
1. ✓
  Gradient formulaGradient $= \frac{Δ E}{Δ \frac{1}{r ^{2}}}$
  1 mark · Read a graph of results
2. ✓
  Substitution of the gradient $680 = \frac{E _{A} - ( 0 )}{\dots}$
  1 mark · Read a graph of results
3. ✓
  Substitution of 1/r² $680 = \frac{E _{A} - ( 0 )}{\frac{1}{0 , 0 4 ^{2}} - ( 0 )}$
  1 mark · Read a graph of results
4. ✓
  Answer with unit $E_{A} = 4, 25 \times 1 0^{5}$ N·C $^{- 1}$
  1 mark · Read a graph of results
6. Question 9.3.1 · November 2025 · Paper 1 · Provincial · 3 marks
Learners investigate the relationship between current in a conductor and the potential differences across the ends of the conductor. The graph below is obtained from their investigation.
9.3 The learners intend to use the conductor to construct an electric heater that should be rated $150$ W and draw a maximum current of $6$ A.

Answer the following questions.
9.3.1 Calculate the gradient of the above graph.(3)
Show the memo (3 ticks)Memo
1. ✓
  Gradient formulaGradient $= \frac{Δ I}{Δ V}$
  1 mark · Read a graph of results
2. ✓
  Substitution of two pointsGradient $= \frac{0 , 6 - 0 , 2}{2 , 5 - 0 , 85}$
  1 mark · Read a graph of results
3. ✓
  AnswerGradient $= 0, 24$
  1 mark · Read a graph of results

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