Ohm's Law
What is the equation for Ohm’s Law?
V = IR
A switch is closed. What happens to the circuit?
Current flows
What happens to current if resistance increases?
Current decreases
How many paths does a series circuit have?
One path
What creates an electromagnet?
Electric current through a wire
Find current.
V = 12 V
R = 4 Ω
I = V/R
I = 3 A
A switch is open in a circuit. What happens to the current?
No current flows (circuit is broken)
What happens to resistance if wire length increases?
Resistance increases
How many paths does a parallel circuit have?
Multiple paths
What metal core is often used in electromagnets?
Iron
Find voltage.
I = 2 A
R = 6 Ω
V = IR
V = 12 V
In a parallel circuit, one light bulb burns out. What happens to the other bulbs?
They stay on
What happens to resistance if wire diameter increases?
Resistance decreases
In which circuit does current stay the same throughout?
Series circuit
What happens if you increase the number of coils?
Magnet becomes stronger
Find resistance.
V = 20 V
I = 4 A
R = V/I
R = 5 Ω
In a series circuit, one bulb burns out. What happens to the other bulbs?
All bulbs go out because the circuit is broken.
What happens to resistance if temperature increases?
Resistance increases
Which circuit is used in homes?
Parallel circuits
What happens to an electromagnet if current increases?
Magnetic strength increases
A circuit has:
V = 24 V
R = 6 Ω
Find current.
I = 24 / 6
I = 4 A
A circuit contains two bulbs in series and a switch placed between them. If the switch is opened, what happens to both bulbs?
Both bulbs turn off because the circuit is broken.
Which wire allows more current?
A long thin wire
A short thick wire
Short thick wire
Why are parallel circuits useful in homes?
Devices work independently
Name two ways to make an electromagnet stronger.
Increase current
Increase coils
Add iron core