Ohms Law Current voltage resistance Using the diagram

Ohm‘s Law

Current, voltage, resistance • Using the diagram on the right, can you explain what current, voltage and resistance are?

Current, voltage, resistance (Write these) • Current: Rate of flow of electric charge. It is measured in Amps (A) • Voltage: Potential difference is a measure of the difference in charge across a component. It is measured in Volts (V) • Resistance: a measure of how much a material tries to stop electricity passing through it. It is measured in Ohms (Ω)

Ohm’s Law • The current through a conductor is directly proportional to the voltage across the conductor, assuming resistance and temperature are constant.

How can we work out voltage using resistance and current? • See if you can write an equation to work out voltage using current and resistance (hint: think about what voltage is, and how resistance affects current) • Voltage(V) = Current(A) x Resistance(Ω) • V=IR

Calculations a) b) Current (A) Potential difference (V) 4. 0 3. 0 20 c) d) e) f) 0. 50 0. 25 50 12 6. 0 Resistance ( ) 15 200 60 30

Solutions a) b) c) d) e) f) Current (A) Potential difference (V) 4. 0 3. 0 0. 25 0. 50 0. 25 0. 2 20 45 50 12 15 6. 0 Resistance ( ) 5. 0 15 200 24 60 30

Ohm’s Law Describe the similarities in the symbols. Do you know what any of them represent?

Easy Medium Hard Calculate voltage if current is 20 A and resistance is 0. 5 Ohms. 20 A and resistance is 7 ohms. Calculate voltage if current is 10 A and resistance is 15 Ohms. 60 A and resistance is 7 ohms. Calculate voltage if current is 3 A 300 A and resistance is 0. 5 Ohms. and resistance is 2 ohms. Calculate voltage if current is 20 A and resistance is 1. 5 Ohms. 70 A and resistance is 7 ohms. Calculate voltage if current is 150 A and resistance is 0. 2 Ohms. 30 A and resistance is 9 ohms. Calculate voltage if current is 30 A and resistance is 5 Ohms. 1. 5 A and resistance is 7 ohms. Calculate resistance if current is 7 A and Voltage is 9 V. Calculate resistance if current is 9 A and Voltage is 9 V. Calculate resistance if current is 18 A and Voltage is 9 V. Calculate resistance if current is 7 A and Voltage is 20 V. Calculate resistance if current is 8 A and Voltage is 2 V. Calculate resistance if current is 13 A and Voltage is 4 V. Calculate voltage if current is 210 A and resistance is 0. 7 Ohms. Calculate resistance if current is 21 A and Voltage is 6 V. Calculate voltage if current is 40 A and resistance is 8 ohms.