Efficiency Year 10 Physics

Efficiency is...

• The amount of useful energy

• The proportion of wasted energy out to total energy in

• The proportion of useful energy out to total energy in

• The proportion of total energy in to total energy out

Tags

NGSS.HS-PS3-3

NGSS.HS-PS3-4

The equation is...

• useful energy / total energy

• wasted energy / total energy

• total energy/ useful energy

• total energy/ wasted energy

Wasted energy is often lost as...

• Kinetic energy

• Elastic potential energy

• Gravitational potential energy

• Heat to the surroundings

Tags

NGSS.HS-PS3-4

What is the unit of energy?

• Joule

• Newton

• Watt

• Ohm

What is the energy transformation in a battery?

• Chemical to Electrical

• Electrical to Chemical

• Thermal to Electrical

• Electrical to Thermal

What is the energy transformation in a light bulb?

• Electrical to Light

• Light to Electrical

• Chemical to Light

• Light to Chemical

Tags

NGSS.HS-PS3-3

A kettle uses 100,000J of energy to boil some water. The water gains 80,000J of thermal energy. What is the efficiency?

• 80%

• 0.80

• 20%

• 0.20

Tags

NGSS.HS-PS3-4

A women does 100J of work climbing some stairs. She gains 60J in GPE (gravitational potential energy), what is the efficiency?

• 0.40

• 0.60

• 40%

• 60%

Tags

NGSS.MS-PS3-4

A car motor is 50% efficient. If it uses 100MJ of energy from the fuel, how much energy is wasted?

• 50MJ

• 25MJ

• 70MJ

• 100MJ

Tags

NGSS.HS-PS3-3

A machine is 75% efficient. If it uses 200J of energy, how much energy is useful?

• 150J

• 50J

• 100J

• 200J

Tags

NGSS.HS-PS3-1