What current, in units of milliAmperes, would produce a potential difference of 4.5

V across a 79 Ω resistor?

Answer;

= 56.96 mA

Explanation;

From the Ohm's law;

V = IR, where V is the potential difference in volts, I is the electric current in amperes and R is the resistance in ohms.

V = 4.5 volts, R = 79 Ω

Making I the subject of the formula we get;

I = V/R

= 4.5 / 79

= 0.05696 A

But, 1 A = 1000 mA

Thus; 0.05696 * 1000

= 56.96 mA