Question

if the wire of lenght L is cut into 3 equal parts then what is the ratio of initial resistance and new resistance?

Answer 1

Hey mate!!

Here;s your answer

If the pieces are of equal length, then you can think of it two ways.

First consider if instead of cutting the wire, you just folded it over on itself. Then the new arrangement would have 1/3 the length and 3 times the cross-sectional area. Resistance is proportional to the length and inversely proportional to the cross-sectional area. Therefore the resistance would be 1/3 of 1/3 of L, which is L/9.

Or do it with the parallel resistance formula. Each piece has an equal amount of the resistance, so L/3.

The formula for resistances in parallel is 1/total = 1/a + 1/b+1/c.

1/(L/3) = 3/L

1/total = 3/L + 3/L + 3/L = 9/L

So total = L/9

Hope it helped you.....Please mark me as brainliest......