An electric motor winds 200 turns of a thin coper wire on a unifrom of diameter 10 cm, in 2 seconds.then the length of the wire that is wound over the rod in one second is _______ m.

Options

A. 30
B. `10pi`
C. `20pi`
D. None of these

Answer

B

Explanation

Number of turns wound over rod = 200
Diameter of the rod, (d) = 10 cm
R = 5 cm = 0.05 m
Time taken to wind, (t) = 2 s
Length of the wire wound in one second = `("distance")/("time")`
= `(200xx2pir)/2=(200xx2pixx0.05)/2=10pim`