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?
i = v / r
and
r = L
200 = 60 / r
r = 10 / 3
cut wire in half means r = 10 / 6 or 5 / 3
i = 400 / 5 / 3
i = 240
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 resistiance is halved)
increasing the volatage ACROSS the wire will increase the amps by 400 / 60
400 / 60 * 400 ma = 2666.7 mAmps
(NOTE : Voltage is apllied ACROSS a component ....not THROUGH it)
(current goes THROUGH a componet)
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