Example: L of Long Solenoid The magnetic induction inside a long solenoid is B N where N'Nl is the number of turns per meter Thus the flux is 重=B.丌R2=1NM and the total flux linkage through the solenoid is A=ND=HON'NITR2 So the self inductance is L==140NNR2=A0 A Thus the self inductance∝xN2and∝丌B2