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I need help with this

 

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 60 volts through this wire and measure 200 milliamps of current.  If I cut the wire in half and pass 400 volts through it, how many milliamps of current will I measure?

 Jun 26, 2023
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I==V/R
R==V/I


200 milliamps ==200 / 1000 =0.2 amps.
R==60 / 0.2 ==300 ohms.
300 / 2 ==150 ohms - resistance in 1/2 of original wire.


I ==V/R
I==400 / 150 ==2.67 amps.
2.67 x 1,000 ==2,670 milliamps of current.

Cutting the wire in half will increase the amps by a factor of 2   to   400 ma         (because the resistance is halved)

  increasing the voltage ACROSS the wire will increase the amps by  400 / 60    

     400 / 60  *  400 ma = 2666.7 mAmps 

 Jun 27, 2023

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