Page 120 - Physics Form 5 KSSM_Neat

5. Repeat steps 2 to 4 with the nichrome wire. Note
V
6. Calculate the resistance, R = for each type of wire.
I Ensure the wire temperature
7. Record all the values of current, I, potential difference, V is constant throughout the
and resistance, R in Table 3.8. experiment as changes in the
temperature will affect the
Results: resistance of the wire.
KEMENTERIAN PENDIDIKAN MALAYSIA
Table 3.8

Type of wire Current, I / A Potential difference, V / V Resistance, R / Ω
Constantan

Nichrome

Conclusion:
What conclusion can be drawn from this experiment?
Prepare a complete report of this experiment.
Table 3.9
Discussion:
The resistivity of different conductors is Material Resistivity of conductor, r / Ω m
given in Table 3.9. What can you say about Copper 1.68 × 10 –8
the resistance of copper wire compared to
Constantan 49 × 10 –8
the resistance of constantan and nichrome
wires? Explain. Nichrome 100 × 10 –8

Based on the results of Experiments 3.2, 3.3 and 3.4, the factors that affect the resistance of
a wire can be summarised as shown in Figure 3.21.

R fi l rl
R = A
l
R fi A where r = the proportional constant known
R fi 1 as the resistivity of the conductor
A
Figure 3.21 Summary of the factors affecting the resistance of a wire
Applications of Resistivity of Conductors in Daily Life

How can you apply your knowledge of resistivity in your daily life?

Activity 3.3 ISS

Aim: To study and elaborate on the applications of resistivity of conductors in daily life
Instructions:
1. Carry out this activity in groups.
2. Gather information to study the applications of resistivity of conductors on:
(a) heating elements
(b) electrical wiring at home (fuse and connecting wires)
3. Prepare a short report on the applications of resistivity of conductors.
110 LS 3.2.4 3.2.5