1. Ohm’s Law & Electrical Power

2. Ohm’s Law
To be functional, every circuit needs at least a voltage source, conducting material to carry the current, and an element with resistance.
Ohm’s Law shows the relationship between current, voltage, and resistance of the whole circuit, a portion of the circuit, or a single element.
𝑐𝑢𝑟𝑟𝑒𝑛𝑡= 𝑣𝑜𝑙𝑡𝑎𝑔𝑒 𝑟𝑒𝑠𝑖𝑠𝑡𝑎𝑛𝑐𝑒 𝐼= 𝑉 𝑅

3. Example Problem
A flashlight uses a 3.0V battery to power a light bulb with 15Ω of resistance. How much current is running through the wire in the flashlight?

4. Example Problem
What is the resistance of a blender that is powered by 110V and has 1.4A of current running through it?

5. Example Problem
A 60 watt light bulb is lit by 0.55A of current. If the resistance of the light bulb is 220Ω, what voltage is used in the circuit?

6. Electrical Power
Measurement of the rate at which electrical energy is transferred through an electrical circuit.
Measured in watts, W
𝑒𝑙𝑒𝑐𝑡𝑟𝑖𝑐𝑎𝑙 𝑝𝑜𝑤𝑒𝑟= 𝑣𝑜𝑙𝑡𝑎𝑔𝑒 𝑐𝑢𝑟𝑟𝑒𝑛𝑡
𝑃=𝑉𝐼

7. Example Problem
A 1.5V battery powers a night light containing a light bulb with a resistance of 0.30Ω . What is the power rating of the light bulb?

8. Example Problem
A crockpot with 57Ω of internal resistance draws 2.1A of current from a circuit. How much power is consumed by the crockpot?