Efficiency = 75%
Step-by-step explanation:
Step 1:
During initial transformation, 100 J of Chemical energy is transferred to 90 J of Electrical energy with a loss of 10 J due to Chemical reaction drop.
And then the Electrical form of energy is transferred into Kinetic or Mechanical energy for toy car usage. Here 15 J of energy is wasted in the form friction and Wear and Tear loss. Since Electrical to Kinetic energy conversion takes place with frictional loss .
Step 2:
So finally the available energy for usage is 75 J.
To find the efficiency the required formula is
Efficiency = (( Useful Power) / (Total Power)) * 100
=
= 75 %