Lesson 3 — Current

• Science
• Middelbare school
• havo, vwo
• Leerjaar 2

Class layout – Science

Class layout – Science

Chapter 9 Electricity

Circuits

• Recap
•  Checking the homework
• Current
• Series and parallel circuits

Recap

What does this symbol stand for in a circuit diagram?

1. A blocker of electric flow
2. A battery
3. A heating element
4. A lamp

Will there be a flow of electric current in this circuit?

There are two correct answers

1. No, because the switch is open
2. Yes, because the switch is closed
3. Yes, because the two poles of the battery are connected
4. No, because the two poles of the battery are not connected

What direction will the electric current in this circuit flow in? (from the point of view of the battery)

1. Left to right
2. right to left

What direction will the electric current in this circuit flow in? (from the point of view of the battery)

1. Left to right
2. right to left

Electricity is:

A flow of electrons from a negatively charged pole to a positively charged pole.

Circuits

Doorbel

loudspeaker

electricity — three core properties

• Current
• voltage
• Resistance

Current

Current

In water: 

• The amount of water that flows by per second
• Expressed in: liters / second

In electricity:

• The amount of electric charge that flows by per second
• Expressed in: coulombs / second (ampere)
• Note: 1 coulomb is 6.24 • 10¹⁸ electrons.

Current

The amount of electric charge that flows by per second.

• Expressed in: Ampere
• 1 ampere is 1 coulomb/ second

1 coulomb stand for 6.24 • 10¹⁸ electrons

Current

The amount of electric charge that flows by per second.

The unit of current is: Ampere (A)

• One ampere is one coulomb / second
• One coulomb is 6.24 • 10¹⁸ electrons.

Ampere can also be expressed in:

milliampere (mA) — 1A = 1000 mA

I=​t​​Q​​

I: current (ampere)
Q: charge (coulombs)

t: time (seconds)

Link

ammeter

ammeter

Series and parallel circuits

Parallel circuit

series circuit

Homework

Worksheet - the word problems

9.6 The yellow block exercises