+1349 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?
+3245
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?
V = IR ==>> R = V / I
R = 500 / 25 mA
R = 500 V / 0.025 A
R = 20,000 Ω
(1/2) • 20,000 Ω = 10,000 Ω
V = IR ==>> I = V / R
I = 175 V / 10,000 Ω
I = 0.0175 A
I = 17.5 mA
I don't like the expression "pass volts through a wire" but I won't quibble.
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