A winding wire which is used to frame a solenoid can bear a maximum 10 A. current If length of solenoid is 80 cm and its corss sectional raedius is 3 cm , then required length of winding wire is (B =0.2T)

Options

A. `1.2 xx 10^(2)` m
B. `4.8 xx10^(2)` m
C. `2.4xx10^(3)` m
D. `6xx10^(3)` m

Answer

3

Explanation

`B=mu_(0)Ni/l`
where N = Total number of turns, l= length of the solenoid
`rArr 0.2=4pixx10^(-7)xxNxx10/0.8 rArr N=4xx10^(2)/pi` Since N turns are made from the winding wire so length of the wire
`(L) = 2pixx N``[2pi r =` length of each turns]
`L=2pi xx3xx10^(-2)xx4xx10^(4)/pi`
`rArr 2.4 xx 10^(3)`m