Chapter Name: Electric Current
Activity Name: Resistance of a conductor in Electric Current
In this experiment, we investigate the resistance of different metal rods with the same length and cross-sectional area. We set up a circuit with P and Q as the free ends of conducting wires. The metal rods (e.g., copper, aluminum, iron) are connected between P and Q one by one.
By measuring the electric current using an ammeter, we observe that the current values differ for each metal rod despite having a constant potential difference. This variation in current values indicates that the resistance of a conductor depends on the material used.
- Different metal rods (e.g., copper, aluminum, iron) with the same length and cross-sectional area
- Conducting wires
- Circuit setup (as shown in figure 14)
- Notebook for recording observations
Step by Step Procedure:
- Gather different metal rods with the same length and cross-sectional area.
- Set up the circuit with conducting wires and connect the ammeter to measure electric current.
- Connect one metal rod between the free ends P and Q in the circuit.
- Switch on the circuit and note the electric current value in the notebook.
- Repeat the process for other metal rods, recording electric current values each time.
The electric current values differ for each metal rod when connected between P and Q, even though the potential difference is kept constant.
- Ensure all connections are secure and properly made in the circuit.
- Take care while handling the metal rods and conducting wires to avoid any accidents or injuries.
- Use appropriate safety measures while working with electricity.
Lesson Learnt from Experiment:
From this activity, we learn that the resistance of a conductor depends on the material it is made of. Different metals have different resistivity, which leads to varying electric current values in the circuit, even when the potential difference remains constant.