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 300 milliamps of current. If I cut the wire in half and pass 800 volts through it, how many milliamps of current will I measure?

Guest Jan 25, 2021

#1**0 **

We place 50 volts across this wire and measure 300 milliamps of current THROUGH the wire

(Voltage does not go THROUGH a wire....current does)

V = IR 50 = .3 (R) R = 166 2/3 ohms (300 mAmps = . 3 Amps )

Cut wire in half R_{2} becomes 1/2 original : 1/2 (166 2/3) = 83 1/3 ohms

WIth 800 V applied:

V = IR

800 = I * 83 1/3 I = 800/(83 1/3 ) = 9.6 amps which is 9600 mAmps

Guest Jan 25, 2021