Q) What is the resistance of a circuit in which a current of 3 amperes flows through a resistor connected to 90 volts?
A) 30 ohms
NJ2X Notes:
Ohm's Law was discovered by Georg Simon Ohm and is worth committing to memory:
E = I * R
or by manipulating the terms algebraically:
I = E / R
or
R = E / I
In this example:
R = E / I
R = 90 volts / 3 amperes = 30 ohms