Question

Find the voltage drop in an extension cord having a 0.0500– Ω resistance and through which 5.70 A is flowing.

A cheaper cord utilizes thinner wire and has a resistance of 0.095 Ω. What is the voltage drop in it when 5.70 A flows? (Why is the voltage to whatever appliance is being used reduced by this amount? What is the effect on the appliance?)

Answer 1

Voltage drop V = IR , where I = current through the extension cord and R= resistance.

so voltage drop across the first extension cord = V =  5.70 A x 0.0500Ω = 0.285 Volts.

so V = 0.285 volts.

And

the voltage drop across the cheap extension cord= V = IR = 5.70 A X 0.095 Ω = 0.5415 Volts

so V= 0.5415 volts

The reduction of the voltage by this amount is due to the resistance of the appliance { in real life all appliance have some resistance(R) , so there must be some reduction of voltage V= IR )

The effect of this voltage drop results in the power dissipation by the appliance which is the product of the voltage drop and the current through the appliance. This dissipated power heated the appliance according to Joule's law)

Thank You.