6.5 Electircal energy

• Physics
• Middelbare school
• vwo
• Leerjaar 3

§6.5 Electrical Energy

Lesson plan:

1. Freshing up our memories + adding Science book online
2. Explanation Power of electrical appliances
3. Practice exercises §6.5 
4. Checkpoint §6.5

Testweek: chapter 6 electricity

Learning goals §6.5

• You can explain what the power of an appliance is and how that is related to energy consumption. 
  
  
• You can do calculations with the formula E = P * t 
• You can calculate from energy consumption to energy costs

Meter 2 is ....
and measures...... in ........

1. an ammeter; voltage in volts
2. a voltmeter; voltage in volts
3. an ammeter; current in amperes
4. a voltmeter; current in amperes

Which letter do we use as abbreviation for the quantity 'electrical current'?

electricity at home

Which device uses more electrical energy?

Electrical power

Energy=Power⋅time

E=P⋅t

New physical quantity:

Power

Unit of power:

• Watt (W)
  
• Kilowatt (kW) 

Formula

• E: energy (kWh)
• P: power (kW)
  
• t: time (h)

The amount of energy something generates or uses per unit of time.

Example: A LED light has a power

of 9 watts.

Calculate the energy consumed by a 120W toaster in 20 minutes. Use the given-asked-solution method in your notebook and give the final answer here.

Calculate how much the energy costs are of you vacuum clean your house for 20 minutes. You use a 850 W vacuum cleaner. 1 kWh costs 0,69 euros. Work it out completely in your notebooks and only copy the final answer here.

Learning goals §6.5

• You can explain what the power of an appliance is and how that is related to energy consumption. 
  
  
• You can do calculations with the formula E = P * t 
• You can calculate from energy consumption to energy costs

Checkpoint: what is the formula for energy consumption of a device?

Get to work!

Choose: 

- Finish exercises 6.4

- Do 55 u/i 67 of 6.5