Electricity
How does electric current flow in a circuit and transfer energy?
16 lessons
Lessons
Direct-current circuits
Chapter 1Electric circuit, current and voltageWhy does the lamp of a torch light at the same moment as you press the switch, although the electrons in the wire move more slowly than a snail?
- Chapter 2Measurements in an electric circuit
Why is an ammeter connected to a circuit in a different way from a voltmeter, and what happens if the connections get mixed up?
- Chapter 3Resistance and Ohm's law
Why is the heating wire of a toaster made of thin special metal, while the conductors of an extension cord are thick copper?
- Chapter 4Resistors in series and in parallel
Why do all the bulbs of an old string of fairy lights go out when one bulb breaks, while at home the floor lamp stays on even when the desk lamp is switched off?
- Chapter 5Kirchhoff's laws and potential in a circuit
Why can a bird sit on a bare high-voltage wire unharmed, even though a current of hundreds of amperes flows in the wire?
Electrical energy and sources
Chapter 6Electric power and the heating of a resistorWhy do the resistance wires of a toaster glow red while the toaster's cord stays cool, even though the same current flows through both?
- Chapter 7Electrical energy at home
Why is an electricity bill calculated from kilowatt-hours and not from the watts of the home's devices?
- Chapter 8Electromotive force and internal resistance
Why do the headlights of a car dim for a moment when the engine is started on a cold winter morning?
- Chapter 9Batteries and the charging circuit
Why does a phone battery charge quickly at the start, but the last few percent take a long time?
Electric charge and field
Chapter 10Electric charge and Coulomb's lawWhy does a balloon rubbed on a wool sweater stick to a wall, although the wall has no electric charge?
- Chapter 11Uniform electric field
Why do the dust particles of an air purifier end up on the surface of the plates of the device, although the air flows past the plates?
- Chapter 12Potential energy and potential in an electric field
Why are the electrons plunging into the upper atmosphere in the aurora so fast that they make the air glow?
- Chapter 13The capacitor and its energy
Why does the flash of a camera need a few seconds of charging time, although the flash itself lasts only a millisecond?
Components and safety
Chapter 14Semiconductors, the diode, the LED and the solar cellWhy does an LED light up only when it is connected one way round, and why does it always need a resistor, although a light bulb can be connected straight to a battery?
- Chapter 15Electrical safety at home and at work
Why does the kitchen fuse trip when many devices are on at the same time, even though none of them is broken?
- Chapter 16Applied chapter: the electric car and the home electrical system
Why should an electric car not be charged through an extension cord from an ordinary socket, and is the electricity of a home enough for the sauna and for charging the car at the same time?
Apply independently
At the end of the module you can try whether you can apply what you have learned independently, in the style of the matriculation examination. The model answers and marking guides open after your own solution.
- Apply independently 4 tasks · 60 points
Module goals
Show all 3 goals
The student
- can investigate electrical phenomena experimentally and make basic electrical measurements
- can use the concepts of field and potential to describe the electric field
- knows safety aspects related to electrical devices and the transmission of electrical energy