An electric motor is needed to provide $120\,\text{W}$ of mechanical output power. The motor’s efficiency is $80\%$. Which row is correct?
- Aelectrical power input to motor $=120\,\text{W}$; waste heat output from motor $=24\,\text{W}$
- Belectrical power input to motor $=120\,\text{W}$; waste heat output from motor $=96\,\text{W}$
- Celectrical power input to motor $=150\,\text{W}$; waste heat output from motor $=30\,\text{W}$
- Delectrical power input to motor $=150\,\text{W}$; waste heat output from motor $=120\,\text{W}$