Name: ______Block: ______
Science 9 – Ch. 10 Current Electricity
10.4 Resistors and Ohm’s Law (pg. 315-319)
Resistor:
· A component in a circuit that ______or ______the flow of electrons and electrical current.
· It is the ______in a circuit that converts electrical energy into another form.
· Units: ______(”omega”)
· There are many different types of resistors. They can be made up of different materials (metal or plastic), different lengths and diameter.
The Colours of Resistance:
· The colour bands represent different values of that resistor
· The first two bands = the ______
· The third band = # of ______to be added
· Example:
o 50 ohm resistor: ______
o ______ohm resistor: brown, green and brown
Resistance:
A measure of how much the material of a conductor ______.
Ohm’s Law
· Describes the relationship between ______.
· or
· If voltage ______, current ______and resistance ______.
· If voltage ______, current ______and resistance ______.
· Resistance can be increased by adding more ______in the circuit.
· Voltage can be increased by adding more ______in the circuit.
Practice:
1. A flashlight uses two 1.5 V cells in series. The current in the bulb is 280 mA. What is the resistance of the bulb? (1000 mA = 1A)
2. A current of 150 mA flows through a 64 Ω resistor. What is the voltage across the resistor?
3. A 22 Ω resistor has a voltage of 3.5 V. What is the current in the resistor? Give your answer in mA.
In Summary:
______- is the flow of electrons round the circuit.
______- is the driving force that pushes the current around.
______- is anything in the circuit that slows the flow down.
Now imagine a river…
“Voltage” = flow rate between 2 points along the river
“Current” = the amount of water passing between the 2 points
“Resistance” = rocks and sand in the river that slows down the water flow
HW: Text pg. 319 CYU Q 2, 3, 4, 5, 6, 7, 9, 10;
Ohm’s Law Worksheet;
Quiz 10.3 – 10.4 next class (Bring a calculator!!!)