All I need help on, is the first one on the top row. Thanks :))

All I Need Help On Is The First One On The Top Row Thanks class=

Answer :

13J is wasted energy.
The wasted energy is thermal energy (heat).
The light bulb’s efficiency is 67.5%

Answer:

1a)40-27=13

1b) heat

1c)efficiency = W out/W in

so 27/40= 67%