Answer:
The voltage (V)
Explanation:
Ohms, in his law, has explained the relationship between current, resistance and voltage.
Ohm's law, which states that the voltage passing through a resistor is directly proportional to both the current and the resistance of the resistor, has the following equation:
V = IR
Where;
V = voltage (volts)
I = current (Amperes)
R = resistance (ohms)
According to this question, Karl measures the current, I, through a resistor. In order to calculate his resistance, R, he will need to measure the voltage, V.
