Energy efficiency

The law of conservation of energy states that when one form of energy is converted into another,

• energy is destroyed in the process
• no energy is destroyed in the process
• energy is created in the process
• some amount of energy cannot be accounted for

Tags

NGSS.HS-PS3-3

The process of energy changing from one form into another

• efficency
• law of conservation of energy
• energy transformation
• thermal energy

Tags

NGSS.MS-PS3-3

NGSS.MS-PS3-4

NGSS.MS-PS3-5

In energy transformations, "wasted energy" usually takes what form?

• heat
• chemical energy
• light
• sound waves

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-3

Efficiency is calculated by useful energy output divided by total energy input, expressed as a percentage

• False

• True

What type of device might this Sankey be about?

• A very efficient LED light bulb
• A very inefficient incandescent light bulb
• A coal power plant
• A wind turbine

Tags

NGSS.MS-PS3-3

NGSS.MS-PS3-4

No machine in existence has 100% efficiency due to ____________________.

• magic
• friction
• smoke
• input

Total energy = 200J
Useful energy = 20J

Workout the efficiency of this lightbulb.
 $efficiency\ =\ \frac{useful\ enegy}{total\ energy\ in}\ \times100$  

• 100%

• 80%

• 40%

• 10%

Tags

NGSS.MS-PS3-4

Total energy = 350J
Useful energy = 70J

Workout the efficiency of this iphoneX.
 $efficiency\ =\ \frac{useful\ energy}{total\ energy\ in}\ \times100\%$  

• 100%

• 80%

• 40%

• 20%

This car needs 8600J of energy to power it. If 5000J is changed into useful energy, how much energy is wasted?

• 13600J

• 3600J

• 5000J

• 8600J

Tags

NGSS.MS-PS3-1

NGSS.MS-PS3-5

Where does most of the energy go in this transformation.

• Electrical energy
• Light
• Heat
• other

Tags

NGSS.MS-PS3-4