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?

parmen Sep 7, 2024

#1**+1 **

**If I cut the wire in half and pass $175$ volts through it, how many milliamps of current will I measure?**

\(R=\frac{V}{I}=\frac{500V}{25\cdot 10^{-3}A }\\ R=20 k\Omega\)

The resistance of the two halves of the wire in combination is \(R_2=\frac{20k\Omega}{4}=5k\Omega .\)

\(I=\frac{V}{R_2}=\frac{175V}{5\cdot 10^3 \Omega}\cdot \frac{10^3mA}{A}\\ \color{blue}I=35mA\)

The current of the two halves of the wire in combination is 35mA.

!

asinus Sep 8, 2024