Question

In an electrical circuit, the voltage across a resistor is directly proportional to the current (amps) running through the resistor. If a current of 12 amps produced 480 amps volts across a resistor, how many volts would a current of 1.5amps produce across an identical resistor?

Answer 1

since it's the same resistor so R is constant
R = V/I =480/12=40
when I = 1.5 , V/1.5 =40 , V = 1.5 x 40 = 60 v

Answer 2

Voltage across resister is 60 V.

Explanation:

It is given in the question that voltage across the resister is directly proportional to the current.

So, V ∝ i

or V = Ki (where K is a proportionality constant)

`K=(V)/(i)`

For all different values of voltage and current,

`(V_(1) )/(i_(1) )= (V_(2) )/(i_(2) )` = K

By substituting values in this formula,

`(480)/(12)= (V_(2))/(1.5)`

`V_(2)=(480* 1.5)/(12)`

= 60 volts

Therefore, voltage across the resister will be 60 volts when the amount of current flowing through the resistor is 1.5 amps.