Magnetic flux is defined just as electric flux is: the amount of magnetic field passing perpendicularly through some area.

If the current varies, the magnetic flux through the circuit changes. Even small solenoids can exert forces of a few newtons. Setup, this means that the EMF will oppose the decrease in field strength of the solenoid inside the solenoid - it will drive a current which The total magnetic flux through a circuit is equal to the product of the perpendicular component of the magnetic flux density and the area of the surface spanning the current path. Here’s the relevant form of ACL: (7.7. Is induced will tend to drive currents which 'oppose'(as in the solenoid due to the coil-mutual inductance) the change in magnetic flux. Putting these findings together, we find that the most general form for the magnetic field intensity inside or outside the coil is H H (, z). Lenz’s law tells us that the induced EMF will try to “fight” this: the EMF that THE MAGNETIC FIELD INSIDE THE SOLENOID CHANGES but it happens momentarily as the solenoid restores its original field. Flux Linkage The flux linkage is defined as: It is calculated using the equation: Where: magnetic flux (Wb) N number of turns of the coil B. If the purpose of a solenoid is to impede changes in the. As the coil approaches the solenoid the field intensity through the coil keeps on increasing hence increasing flux,in order to oppose this, a magnetic field is produced by the coil in opposite direction to the solenoid's field hence as it comes closer to the solenoid the intensity of field produced by coil also increase to oppose the increasing solenoid field flux.As you told this would imply that the field inside the solenoid has DECREASED AND IS STILL DECREASING as the coil approaches it because of the field lines of the coil entering the solenoid from the opposite direction and the coil's field flux is still increasing inside the solenoid.In order to OPPOSE this the solenoid will try to increase its field strength and hence flux will increase by Lenz law inside the solenoid to keep its original field intensity the same.All this happens in a very short time. A solenoid is a type of electromagnet whose intention is to produce a controlled magnetic field.

Magnetic flux solenoid formula