1. Charge
and
Current

2. CHARGE Charge is a physical property ,
Objects with charge interact with each other and exert forces on each other.
Like charges:
Opposite charges:
Describe the experiment that discovered the quantisation of charge
State the definition of current
Use Kirchoff’s First Law

3. A coulombs is derived from base units, show how…
Charge is measured in
A coulombs is derived from base units, show how…
The charge on an electron is :
Often represented by a
Learn this, you will use it a lot!
Describe the experiment that discovered the quantisation of charge
State the definition of current
Use Kirchoff’s First Law

4. MILLIKAN’S EXPERIMENT
Describe the experiment that discovered the quantisation of charge
State the definition of current
Use Kirchoff’s First Law

5. MILLIKAN’S EXPERIMENT+ -
Describe the experiment that discovered the quantisation of charge
State the definition of current
Use Kirchoff’s First Law

6. MILLIKAN’S EXPERIMENT
Millikan determined that the charge on the droplets were multiples of elementary charge
Describe the experiment that discovered the quantisation of charge
State the definition of current
Use Kirchoff’s First Law

7. Current is the flow of charged particles
Describe the experiment that discovered the quantisation of charge
State the definition of current
Use Kirchoff’s First Law

8. KIRCHOFF’S LAW
Set up a series of circuits with two or three resistors/bulbs in series and parallel and using an ammeter determine a rule for current through an electrical circuit.
Describe the experiment that discovered the quantisation of charge
State the definition of current
Use Kirchoff’s First Law

9. KIRCHOFF’S LAW Gustav Kirchoff 1824-1887
Describe the experiment that discovered the quantisation of charge
State the definition of current
Use Kirchoff’s First Law

10. KIRCHOFF’S LAW
Describe the experiment that discovered the quantisation of charge
State the definition of current
Use Kirchoff’s First Law

11. KIRCHOFF’S LAW
Describe the experiment that discovered the quantisation of charge
State the definition of current
Use Kirchoff’s First Law

12. QUESTIONS
1. Convert 25 mA to A
2. Convert 0.50 A to mA
3. A torch bulb passes a current of 120 mA.
(a) How many coulombs of charge flow through the lamp in 1 minute?
(b) How many coulombs of charge flow through the lamp in 1 hour?
(c) How many electrons leave the negative terminal of the cell each second?
4. A car battery is rated as 36 A h. In principle this means it could pass a current of 1 A for 36 h before it runs down. How much charge passes through the battery if it is completely run down?
5. An electron beam in a beam tube carries a current of 125 μA.
(a) What charge is delivered to the screen of the tube every second?
(b) How many electrons hit the screen each second?
Describe the experiment that discovered the quantisation of charge
State the definition of current
Use Kirchoff’s First Law

13. QUESTIONS
Describe the experiment that discovered the quantisation of charge
State the definition of current
Use Kirchoff’s First Law

14. CONVENTIONAL CURRENT
Describe the experiment that discovered the quantisation of charge
State the definition of current
Use Kirchoff’s First Law