A long solenoid has `200 turns per cm` and carries a current `i`. The magnetic field at its centre is `6.28xx10^(-2) weber//cm^(2)`. Another long soloenoid has `100 turns per cm` and it carries a current `(i)/(3)`. The value of the magnetic field at its centre is

Options

A. `1.05xx10^(-4)Wb//m^(2)`
B. `1.05xx10^(-2)Wb//m^(2)`
C. `1.05xx10^(-5)Wb//m^(2)`
D. `1.05xx10^(-5)Wb//m^(2)`

Answer

B

Explanation

`(B_(2))/(B_(1))=(m_(0)n_(2)I_(2))/(mu_(0)n_(1)I_(1))=100/200xx1/3=1/6impliesB_(2)=(B_(1))/6=1.05xx10^(-2)Wb//m^(2)`