Question

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?

Answer 1

According to Ohm's law, the current (I) through a wire is directly proportional to the voltage (V) and inversely proportional to the resistance (R). Mathematically, this relationship is expressed as:

I = V/R

Given that the current (I) is directly proportional to the voltage (V), we can write the following proportion:

I1 / V1 = I2 / V2

Where I1 and V1 are the initial current and voltage, and I2 and V2 are the new current and voltage.

In the given scenario, the initial current (I1) is 200 milliamps, the initial voltage (V1) is 60 volts, and the new voltage (V2) is 400 volts. We need to calculate the new current (I2).

Using the proportion, we can rearrange the formula to solve for I2:

I2 = (I1 * V2) / V1

Substituting the given values:

I2 = (200 milliamps * 400 volts) / 60 volts

I2 = 1333.33 milliamps (rounded to the nearest milliamp)

Therefore, if you cut the wire in half and pass 400 volts through it, you would measure approximately 1333 milliamps of current.