Question

If a current flowing through a lightbulb is 0.75 ampere and the voltage difference across the lightbulb is 120 volts, how much resistance does the light bulb have

Answer 1

Answer: $160 \Omega$

Explanation:

According to Ohm's law:  

$V=R.I$  

Where:  

$V=120 V$ is the voltage difference across the light bulb

$R$ is the resistance of the light bulb   (the value we want to find)

$I=0.75 A$ is the electric current

Isolating $R$:  

$R=\frac{V}{I}$

$R=\frac{120 V}{0.75 A}$

Finally:

$R=160 \Omega$  This is the resistance of the light bulb