Describe how the student could use her circuit to investigate how the currentthrough a filament lamp affects its resistance

Understanding the Investigation

To explore how the current through a filament lamp affects its resistance, the student can set up a simple electrical circuit. This investigation will help in understanding the relationship between voltage (V), current (I), and resistance (R) using Ohm's Law, which states that $V = I \times R$.

Steps for the Investigation

1. Set Up the Circuit:

   • Connect a filament lamp, ammeter, and variable resistor (rheostat) in series with a power supply. The ammeter will measure the current flowing through the lamp.

2. Vary the Current:

   • Adjust the variable resistor to change the current flowing through the filament lamp. Start with a low current and gradually increase it while keeping the voltage constant.

3. Measure Voltage and Current:

   • At each current setting, measure the corresponding voltage across the filament lamp using a voltmeter. Record both the current (I, in amperes) and voltage (V, in volts).

4. Calculate Resistance:

   • Use Ohm's Law to calculate the resistance $R$ of the filament lamp at each current setting using the formula: $R = \frac{V}{I}$
   • Perform this calculation for each pair of voltage and current readings.

5. Analyze the Results:

   • Plot the resistance values against current values. This will help visualize the relationship and any trends. Typically, the resistance of a filament lamp increases with increasing current due to the heating effect of the filament.

Conclusion

By following these steps, the student will be able to investigate how the current through the filament lamp affects its resistance. This practical experiment emphasizes the real-world application of Ohm's Law and demonstrates how resistance in materials can change with temperature, a key concept in electrical engineering and physics.