Effiency

Question 1

What is efficiency

Answer 1

Efficiency tells us what fraction of the energy we put into an appliance is transferred to useful forms of energy

Question 2

What’s the two equations for efficiency

Answer 2

Efficiency = useful output energy transfer divided by total input energy transfer
Efficiency = useful power output divided by total power input

Question 3

An electric hob is used to heat water. 15,000 J of thermal energy is transfered by the hob. 12,000 J of thermal energy passes into the water. Calculate the efficiency of energy transfer into the water.

Answer 3

12,000/15,000 =0.8
0.8 (or 80%) Is the efficiency of energy transfer into the water