Page 72 - Physics_Form_2

Physics for Secondary Schools

heat, making the iron hot. Other electrical
5. Two batteries, V and V are appliances that work on the heating effect
,
1
2
connected in series with an 8 Ω of electric current include immersion water
resistor as shown in Figure 2.35. heaters, hot plates, electric kettles and
filament lamps. Activity 2.10, 2.11 and
2.12 illustrates on how one can investigate
FOR ONLINE READING ONLY
V =2 v V =3 v
1 2
heating effects of an electric current.
Activity 2.10
8 Ω

Figure 2.35 Aim: To investigate the heating
effect of an electric current
Given that the internal resistances
of the two batteries are 2 Ω and 1 Materials: Battery, thermometer,
Ω, respectively, determine the p.d resistive wire, ammeter,
across the 8 Ω. voltmeter, rheostat,
6. Look at the three circuit diagrams in stopwatch, calorimeter
Figure 2.36. Rank the circuits from with jacket, connecting
brightest bulb(s) to dimmest bulb(s). wires, water, switch
Explain your choices.
Procedure
1. Determine the resistance, R, of the
resistive wire using a meter bridge
procedure.
2. Set up the apparatus as shown in
A B C Figure 2.37.
Figure 2.36 E
S
R
h
7. A sub-woofer needs a household
voltage of 220 V to push a current
of 5.5 A through its coil. What is the
resistance of the coil? Stirrer

Heating effect of an electric current Calorimeter

When an electric current flows through a Lagging
conductor, the electrical energy is converted Water
into thermal energy, and the conductor heats
up. This is a demonstration of the heating
effect of an electric current. In an electric Thermometer Resistive wire
iron, the electrical energy is converted to Figure 2.37

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Student’s Book Form One

Physics Form 2 Final.indd 66 25/10/2025 10:26