Chapter Name: Electric Current
Activity Name: Thickness of a conductor in Electric Current
This experiment aims to investigate the relationship between the length of a conductor and its resistance, assuming a constant potential difference. Additionally, it explores whether the thickness of a conductor affects its resistance.
- Iron spokes of different lengths with the same cross-sectional areas
- Circuit components (e.g., battery, ammeter, connecting wires)
- Notebooks for recording observations
Step by Step Procedure:
- Gather iron spokes of various lengths with the same cross-sectional area.
- Set up the circuit as shown in figure 14.
- Connect one of the iron spokes (e.g., 10cm length) between points P and Q in the circuit.
- Use an ammeter to measure the current passing through the circuit and record the value in your notebook.
- Repeat the above step for each of the other lengths of iron spokes, noting down the corresponding values of current in your notebook.
After conducting the experiment and noting the values of current for different lengths of iron spokes, you will observe that as the length of the iron spokes increases, the current passing through the circuit decreases. This indicates that the resistance of each spoke increases with an increase in its length for a constant potential difference.
- Ensure all circuit connections are secure and accurate to obtain reliable readings.
- Use the same cross-sectional area for all the iron spokes to maintain consistency.
- Take multiple readings for each length to ensure accuracy and identify any potential outliers.
Lesson Learnt from Experiment:
The experiment demonstrates that the resistance (R) of a conductor is directly proportional to its length (l) for a constant potential difference (V), given that the temperature and cross-sectional area remain constant. This relationship is expressed as R ∝ l (at constant temperature and cross-sectional area) (Equation 1).