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FORM : 3

EVIDENCE : 8

ELEMENT/ CONSTRUCT : Element 1 : C8

Element 2 : C12, C13, C14, C15, C17Element 3 : C17

TOPIC : CHAPTER 6 : ELECTRICITY

EXAMPLES OF STUDENTS REPORT ELEMENT/CON

TRUCT

Topic Relationship between voltage,current and resistance

Aim To study the relationship between

voltage, current and resistance.

E2: C12 (a)

Problem statement What is the relationship between

voltage, current and resistance ?

Hypothesis The ratio of the voltage to the currentin a circuit is constant, which gives

the resistance in the circuit.

E2: C12 ( b )

Variables

a) is kept constantb) is manipulated

c) responding

Value of the resistanceThe change in voltage and current

The ratio of the volage to the current

E2 : C12 (c)

Apparatus Electrical source (0-12V) , ammeter,

voltmeter, switch, connecting wires,bulb and bulb holder.

E2 : C12 ( d)

Diagram

Student are required to draw

the diagram.

E2 : C12 (g)

Procedure 1. You are required to plan and

carry out an experiment to

study the relationship

E2 : C12 (f)

Dry

cell

Bulb

voltmeter

Ammeter

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between voltage, current and

resistance as shown in thefigure above.

2. Get your teachers approval

before starting the

experiment.Method/Steps 1. The electrical circuit was set

up as shown in the figure

above.

2. A 2V electrical source was

connected to the circuit andthe current reading was

recorded.

3. The activity was repeatedusing 4V, 6V , 8V and 10 V

electrical sources.

4. The value of voltage percurrent was calculated .

5. Then , a graph showing the

voltage versus current values

was plotted.

E2 : C13 ( a c )

Observations Voltage(V)

Current(A)

VoltageCurrent

0 0 0

2 0.1 20

4 0.2 20

6 0.3 20

8 0.4 2010 0.5 20

E2: C14 (I iv)

Graph:

E2: C15 (a b)

Discussion Questions

1. What is the relationshipbetween voltage and current?

2. Calculate the gradient of the

graph obtained?3. Deduce the gradient of the

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graph on Ohms Law.

4. Give an operationaldefinition for the resistance

based on the experiment.

Answers:

1.Relationship between voltage andcurrent: The bigger the voltage , the

bigger the current that flows.

2. Gradient of graph = 6 /0.3 =20

3. The Ohms Law deduces that thegradient of the graph is the resistance

of the electrical circuit.

4. Operational definition : Resistanceis the ratio of voltage to the current.

E1: C8 (a) (c)

E1:C8 (b) (d)

E1: C8 (a-b)

Conclusion The ratio of the voltage to the current

is constant and gives the value for

resistance . Thus , the hypothesis isaccepted.

E2: C16 (a-b)