resistance Flashcards
What is a material with many free electrons that passes current freely called?
Conductor
What is a material having few free electrons and passing current with difficulty called?
Insulator
Give examples of a conductor.
- Copper
- Silver
- Gold
Give examples of an insulator.
- Wood
- Plastic
- Rubber
What is the basic measurement of resistance, and what is its symbol?
Ohms
List 4 factors which affect the resistance of a conductor.
- cross sectional area
- Length
- Temperature
- Material type
State Ohm’s Law in full.
Current flowing through a conductor is directly proportional to the applied voltage across it, providing the temperature remains constant, and is inversely proportional to the resistance.
What relationship is Ohm’s Law showing?
Voltage is proportional to Current as long as resistance is constant.
If the resistance in a circuit is constant, what will the current do if the voltage is increased?
Increase
If the voltage in a circuit is constant, and the resistance is decreased what will the current do?
Increase
What do all components in an electrical circuit contain?
Resistance
Which ways can circuit components be connected?
- Series
- Parallel
How is a series circuit connected?
Components are connected end to end.
How is the total resistance found in a series circuit?
By adding the resistances of each component together.
What is the formula for the total resistance in a series circuit?
R_total = R1 + R2 + R3 + …
How many current paths are there in a series circuit?
One
What is the loss of EMF called?
Voltage drop
If we add all the volt drops in a series circuit, what will the voltage add up to?
Total voltage
How is the total resistance found in a series circuit?
By adding them all together.
What is the same through each component in a series circuit?
Current
When components are connected side by side, how are they said to be connected?
In parallel
What is the formula for calculating resistors in parallel?
1/R_total = 1/R1 + 1/R2 + 1/R3 + …
