How many meters of nickel wire with a cross-sectional area of 0.1 mm is required to manufacture

How many meters of nickel wire with a cross-sectional area of 0.1 mm is required to manufacture a rheostat with a maximum resistance of 180 ohms?

The density of the nickel wire is 0.4 ohm * mm ^ 2 / m.

To solve this problem, you must use the following formula:

R = p * l / S,

Where:

R is the resistance value in the section of the conductor;

p is the density of the material;

l is the length of the conductor;

S is the cross-sectional area.

Let us express the length of the wire from the basic formula and get:

l = R * S / p.

Let’s substitute the values from the condition.

l = 180 * 0.1 / 0.4 = 18 / 0.4 = 45 meters.

Answer: The length of a nickel wire with a cross section of 0.1 mm should be 45 meters.