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I/GCSE Physics Question Analysis Topic: Chapter 2: Electricity - Energy and Voltage in Circuits (Part 2)
For I/GCSE Physics, you should know:
Now, let's learn about the second part IGCSE Physics Chapter 2 sub-topic on "Energy and Voltage in Circuits."
Qualitative Effect of Changing Resistance on Current:
- As the resistance in a circuit increases, the current decreases.
- This is due to Ohm's law, which states that the current is inversely proportional to the resistance (I = V/R).
- So, if the resistance goes up, the current will go down, and vice versa.
Variation of Resistance in Components: - Light-Dependent Resistors (LDRs):
- The resistance of an LDR decreases as the illumination on the component increases.
- This makes LDRs useful for light-sensitive applications, such as automatic lighting controls.
- Thermistors:
- The resistance of a thermistor decreases as the temperature increases.
- Thermistors are used in temperature-sensing applications, such as in electronic devices to monitor and regulate temperature.
Indicating the Presence of Current: - Lamps and Light-Emitting Diodes (LEDs) can be used to indicate the presence of current in a circuit.
- When current flows through these components, they emit light, providing a visual indication of the circuit's operation.
Relationship between Voltage, Current, and Resistance (Ohm's Law): - Ohm's law states that the voltage (V) across a component is equal to the current (I) flowing through it multiplied by the resistance (R) of the component.
- The mathematical expression for Ohm's law is: V = I × R
Current as the Rate of Flow of Charge: - Current is the rate of flow of electric charge through a circuit.
- The unit of current is the ampere (A), which represents the flow of one coulomb of charge per second.
Relationship between Charge, Current, and Time: - The total charge (Q) that flows through a circuit is equal to the current (I) multiplied by the time (t) over which the current flows.
- The mathematical expression for this relationship is: Q = I × t
Work hard for your I/GCSE Physics examination!
End of analysis. Great!
