An electric current flows in a conductor when there is a potential difference between its ends - Leaving Cert Physics - Question 9 - 2008

1. Heating Effect: Electric current generates heat when flowing through a conductor, which is utilized in appliances like electric heaters.

2. Magnetic Effect: An electric current produces a magnetic field around the conductor, which is the principle behind electromagnets.

A common source of potential difference is a battery. Other sources include generators and thermocouples.

To investigate if a substance is a conductor, you can use a simple circuit consisting of a power source (like a battery), an ammeter, and a light bulb.

1. Apparatus: Set up the circuit with the power source, ammeter, leads, and the test substance placed between the leads.

2. Procedure: Close the circuit and observe whether the light bulb illuminates. If it does, the substance is a conductor; if it does not, the substance is an insulator.

In the circuit diagram, depict two headlights connected in parallel to a 24 V battery, with wires representing the connections, ensuring that each headlight has its own path to the power supply.

The advantage of connecting the headlights in parallel is that if one headlight fails, the other continues to work, ensuring that at least one light remains operational.

A fuse should be included to provide safety by preventing excessive current that could cause overheating or potential damage to the circuit.

For two resistors in parallel: rac{1}{R_{total}} = rac{1}{R_1} + rac{1}{R_2} Substituting the values: rac{1}{R_{total}} = rac{1}{20Ω} + rac{1}{20Ω} = rac{2}{20} Thus, the total resistance is:
R_{total} = rac{20}{2} = 10Ω

Using Ohm's Law, where $V = I imes R$: To find the current ($I$): I = rac{V}{R_{total}} = rac{24V}{10Ω} = 2.4A Thus, the current flowing in the circuit is 2.4 A.