Question

A person cuts a wire in 10 pieces and then again cuts the wire into 10 pieces and continues to do so , What is the minimum value that the wire gets cutter into 621 to 630 pieces

Answer 1

Answer:

Step-by-step explanation:

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 R, which is R/9.

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

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

1/(R/3) = 3/R

1/total = 3/R + 3/R + 3/R = 9/R

So total = R/9