A long solenoid has 200 turns per cm and carries a current of 2.5 amps. The magnetic field at its centre is `(mu_(0)=4pixx10^(-7)"weber"//amp-m)`
A. `3.14 xx 10^(-2) Wb//m^(2)`
B. `6.28 xx 10^(-2)Wb//m^(2)`
C. `9.42 xx 10^(-2) Wb//m^(2)`
D. `12.56 xx 10^(2) Wb//m^(2)`
