+1678 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 $500$ volts through this wire and measure $25$ milliamps of current. If I cut the wire in half and pass $175$ volts through it, how many milliamps of current will I measure?
+1557 1
If we cut the wire in half, the resistance will also be halved. Therefore, the new resistance will be R/2.
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
Therefore, the new current will be:
I = V/(R/2) = 2V/R
We know that the original current was 25 milliamps, so the new current will be:
I = 2V/R = 2 * 175V / (25mA * 1000) = 14mA
Therefore, the new current is 14 milliamps.
