1. Ohm’s V=IR

2. Wheatstone and Ohm Read story

3. Worksheet on Ohm’s Law Using second hand data.

4. Ohm’s Law Georg Ohm discovered that some items (called Ohmic conductors) will maintain a set resistance value regardless of the voltage that is applied to them. The resistance of ohmic conductors can be calculated using Ohm’s Law: Where: – R = resistance (ohms -  ) – I = current in amps (A) – V = voltage across the components (volts - V) VIVI R=

5. Ohm’s Law However, many items are non-ohmic, (e.g. light bulbs) which means their resistance alters with variations in the voltage that is applied to them. This is because the item has different resistances at different operating temperatures (largely decided by the applied voltage).

6. Ohm’s Law Example: – 4 amps current runs through a kettle’s heating element. The voltage supplied is 240V. What is the resistance of the element? I = 4 amps V = 240 V R = ? V = IR R = V/I R = 240V/4 amps R = 60  – Draw a colour coded fixed resistor to match this element.

7. Problem solving worksheet using Ohm’s law