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In physics, Ohm's law says that current through a wire, \(I\), is directly proportional to voltage, \(V\), and inversely proportional to resistance, \(R\)

\(I=V/R\)

It's also true that resistance is directly proportional to the length of the wire. We have a piece of wire. We pass 50 volts through this wire and measure 200 milliamps of current. If I cut the wire in half and pass 300 volts through it, how many milliamps of current will I measure?

Jul 14, 2020

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I = V/ R

This question has been asked several times before....

Voltage is applied 'across' the wire  (not through it)  and a current of .2 amps passes 'through' it

.2 = 50 / R      Solve for R = 250 ohms

Now cut the wire in half.....this will cut the resistance in half   to 125 ohms

and increase the Voltage to 300

Now the current becomes   I = V/R =  300 / 125 = 2.4 amps   (2400 mAmps)

Edited....  THANX for finding my error , Alan !

Jul 14, 2020
edited by ElectricPavlov  Jul 14, 2020
edited by ElectricPavlov  Jul 14, 2020