Just need help with 2 questions If someone can just give me the formula for the second question i should be right. Q1. A step-up transformer has 100 turns on its primary coil and 300 turns on its secondary coil. Under what conditions would an input voltage of 240V not produce any output voltage? Q2. If the magnetic flux passing through a coil changes from .3 webers to .7 webers in .25 secs, What is the EMF induced in a coil of 200 turns?