The correct answer is B: n1 : n2 = v1:v2
- Electrical power is calculated by multiplying voltage (in volts) by current (in amps).
- If a transformer is 100% efficient, then the input power will equal the output power. ...
- V P is input (primary) voltage.
- I p is input (primary) current.
- V s is output (secondary) voltage.
- I s is output (secondary) current.