2E electricity 4.4 2E Lesson 5

Electricity
§4  Power and energy
Welcome!
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This lesson contains 14 slides, with interactive quiz and text slides.

time-iconLesson duration is: 45 min

Items in this lesson

Electricity
§4  Power and energy
Welcome!

Slide 1 - Slide

Lesson structure
  1. Teacher repeats concepts of previous lesson (5 min)
  2. Teacher explains new concepts around energy and electricty. Student takes notes and asks questions (15-20 minutes)
  3. Work on exercise on workbook (teacher checks homework if the previous lesson) (25-30 min)
  4. Difficult exercises will be explained to the class + end of lesson (5-10 min)

Slide 2 - Slide

Learning objectives
  • You can explain the meaning of 'electrical power'.
  • You can perform calculations with the electrical power of a device.


  • You can analyse mixed circuits (series and parallel combined)

Slide 3 - Slide

Mixed circuits

Slide 4 - Slide

It's like a puzzle
3 important rules:
         1. The current gets divided in parallel and is the same in
             series.
         2. The voltage gets divided in series and is the same in
              parallel.
         3. Ammeters are always in series, voltmeters are always
              parallel!

Slide 5 - Slide

Let's try!

Slide 6 - Slide

Which one of these uses 
more energy?

Slide 7 - Slide

Which one of these uses 
more energy?
It depends on the time!

Slide 8 - Slide

Electrical power
The electrical power is the amount of Joules that an electrical device uses each second.

We measure the power in Watts [W]

Slide 9 - Slide

Electrical power
The electrical power is the amount of Joules that an electrical device uses each second.

We measure the power in Watts [W]

What does the electrical power depend on?

Slide 10 - Slide

Electrical power


P is the electrical power in W
U is the voltage in V
I is the current in A
P=UI

Slide 11 - Slide

Slide 12 - Slide

Your phone charger works on a voltage of 12V.
The package says that it delivers 20W to the
phone. Calculate the current that runs
through the charger.

Slide 13 - Open question

Working on the exercises
Read: p. 139 - 141
Make: 2, 4, 5, 6, 8
And: 11 from paragraph 3
Not finished? --> Homework!

Slide 14 - Slide