Question

What supply voltage would be needed to provide a current of 1.2A through a 40 ohm resistor?

Answer 1

With the use of equation V= IR you are able to solve this probelm

So V=IR
V= 1.2 × 40
V =48v

Answer 2

Voltage = (current) x (resistance).  V = (1.2 A) x (40 ohms)  V = 48 volts