Y2_T2_LSN2.3.

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

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TOPIC 2.3

ELECTRICITY

P. 70-77

§2.3 - Learning Goals:

P. 70-77

I can…:

• Explain what electrical energy is made of.
• Explain what current is, along with its unit of measurement.
• Explain what voltage is, along with its unit of measurement.
• Calculate the power a device uses with the help of the formula P= U • I.
• Calculate the amount of energy a device uses with the help of the formula E = P • t.
• Explain how energy consumption depends on both the power of a device and the time it's used. 

§2.3 - Key Words:

P. 70-77

• Electricity
• Electrons
• Electrical current (I)
• Ampères (A)
• Voltage (U)
• Volts (V)
• Voltage source
• Power (P)
• Watt (W)
• Energy consumption
• 
  
• 
  

Name different sources of electricity

What is an insulator?

1. a material that does not conduct electricity
2. a material that conducts electricity
3. a clamp to connect two electric wires
4. a electric source

§2.3 - What is electricity?

Electricity is caused by the flow of electrons moving through a conducting material

- Those electrons go from the power source to the device

- In the appliance they leave their energy behind

- They go back to the power source to be charged.

The plastic around the wire is an insulator (cable jacket and wire insulation)

The coper wire is a conductor (stripped wire)

There is a electrical current when...

1. the circuit is closed
2. when there is a electric source
3. when the wires are conductors
4. all three need to be true

§2.3 - Current

How many electrons flow past every second.

 

Measured in Amps (A) 

with an am-meter

§2.3 - Voltage

 How much electrical energy each electron is carrying. 

 

Measured in Volts (V) 

with a voltmeter

How much voltage is in an electric socket at your home?

§2.4 - Voltage 

The mains socket has a voltage of 220V 

This can be dangerous and even deadly

24V is the safe limit  

Transformers raise/lower voltage

What is the unit for electrical current?

1. V for Voltage
2. A for amps
3. W for Watts
4. v for Speed

What is the Voltage of a electrical socket in a house?

1. 360 V
2. 12 V
3. 230 V
4. 1500 V

What part of an atom makes it possible for electrical energy to trafel?

1. Proton
2. Nucleon
3. Muon
4. Electron

§ 2.3 - Power

The power of a device is the amount of energy it uses every second.

The power is measured in Watts (W)

Watts is also J/s (joules per second)

§ 2.3 - Power

Power can be calculated with the formula:

P = U x I 

• P for Power (in W)
• U for Voltage (in V)
• I for current (in A)

Energy

Power

Time

Voltage

current

I

P

U

E

t

J

W

s

V

A

I

P

U

E

t

The formula is P = U x I
Witch of these is also correct?

1. U = I / P
2. U = P x I
3. U = P / I
4. U = P + I

A device has a battery of 12 V. There is a current going through the device of 5 A. What is the power of this device?

A telephone has a 15 V battery. Its power in low energy mode is 45 W.
What is the current in the telephone?

A water boiler takes 3 minutes to heat the water. It has a power of 2000 W.
How much energy did the boiler use.

1. 6000 J
2. 667 J
3. 0,015 J
4. 360000 J