Question

The current in a radio measures 12 amps. The resistance of the radio is 4 ohms. What is the voltage?

Answer 1

As per ohm's law we can say that voltage across the ends of a resistor is always product of the resistance with current flows through it.

So we can write

$V = i*R$

given that

i = 12 A

R = 4 ohm

now we can say from the above formula

$V = 4 * 12$

$V = 48 Volts$

Answer 2

Voltage = current * resistance
Voltage = 12 * 4
Voltage = 48V