equations

• wavespeed = frequency x wavelength

• energy transferred = power x time

• efficiency

  useful energy transferred / total energy transferred
• Charge = current x time

• Potential difference = current x resistance

• Potential difference = work done (energy transferred) / charge

• power = energy / time

• Energy transferred (work done) = charge flow x potential difference

• Power = Potential difference x current

• power = (current)^2 x resistance

• force = magnetic flux density x current x length of conductor

• potential difference across primary coil x current in primary coil = potential difference across secondary coil x current in secondary coil

• potential difference across primary coil / potential difference across secondary coil = number of turns in primary coil / number of turns in secondary coil