Question

A very long solenoid has 8400 windings and a length of 7 m. If the field inside is 2ir x iO T, the current in the windings is about [μ /4π = 10^-7 T∙m/A] 

(A) 0.42 A 

(B) 0.83 A 

(C) 4.2 A 

(D) 8.3 A.

Answer 1

Correct option is (C) 4.2 A