Question

A piece of wire having R is cut into 5 equal parts and the five parts are connected in parallel and then in series. What will be the ratio of resistance in parallel to that of series.​

Answer 1

Answer:

25

Explanation:

Resistance of a piece of wire is proportional to its length.

A piece of wire has a resistance R. The wire is cut into five equal parts.

Therefore, resistance of each part =R/5

All the five parts are connected in parallel.

1/R"=1/(5/R) +1/(5/R) + 1/(5/R) +1/(5/R) +1/(5/R)

1/R" =5/R+ 5/R+ 5/R+ 5/R+ 5/R

1/R" =25/R

R"=R/25

then in series connection, R'=R/5+R/5+R/5+R/5+R/5=R

Ratio :: R'/R"=R/(R/25)=25

Thank you