Discussing worksheet

• Natuurkunde
• Middelbare school
• vwo
• Leerjaar 3

Energy

This lesson:

• Discussing goal A and B, worksheet
• Finishing worksheet.  

On how many pages from the worksheet did you work?

Page 1

Page 1 and 2

Page 1 till 3

none

Exercise A page 1 (only fill in the number)

A device with an output of 500 W converts this electrical energy into heat, light and sound. 20% of all electrical energy is converted into sound energy. The device produces 200 W of light energy.

Calculate the amount of heat energy the device produces per second.

Draw the energy flow diagram of the device in question A.

In a hydroelectric dam, the kinetic energy of the water is used to run a generator. This motion energy is then converted to electrical energy in the generator. When converting the motion energy of the water into the motion energy of the generator, 20% of all energy is lost in the form of friction. When converting the motion energy of the generator into electrical energy, 60% is lost in friction.

Draw the energy flow diagram of this dam as a whole.

Calculate the sufficiency of the Lamp. (only fill in the number)

The figure shows the energy flow diagram of a light bulb. In the figure you can see how much light-energy and heat the lamp gives off per second.

Calculate the efficiency of this lamp.

What's the efficiency of the LED lamp? (only fill in the number)

A 50 W light bulb emits the same amount of light as a 10 W LED lamp per second.

What is the efficiency of the LED bulb?

Calculate or reason how big X is. (only fill in the number)

Two lamps produce the same amount of light. Lamp A has an electrical output of 12 W and an efficiency of 20%. Lamp B has an electrical output of X W and an efficiency of 25%.

Calculate or reason how big X is.

Next lesson: 

• Discussing worksheet part 3.
• Requests may be made before Monday 17:00 for repetition on Wednesday.

Een waterkoker met een vermogen van 1000 W en een rendement van 85% wordt gebruikt om 1 kg water (20 °C) te verwarmen tot 40 °C. De soortelijke warmte van water is 4,186 J/g∙°C.

Bereken de tijd die hiervoor nodig is.