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

Answer:

Voltage across resister is 60 V.

Step-by-step 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)

$K=\frac{V}{i}$

For all different values of voltage and current,

$\frac{V_{1} }{i_{1} }= \frac{V_{2} }{i_{2} }$ = K

By substituting values in this formula,

$\frac{480}{12}= \frac{V_{2}}{1.5}$

$V_{2}=\frac{480\times 1.5}{12}$

    = 60 volts

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