The magnitude of the magnetic field due to the current in solenoid 1 can be determined using the equation B = μnI. The magnetic field inside the solenoid is assumed to be uniform in magnitude and direction. Therefore, the magnitude of the magnetic field due to the current i1(t) in solenoid 1 is b1(t) = μn1i1(t).
The magnitude of the magnetic field due to the current in solenoid 1 can be determined using the equation B = μnI, where B is the magnetic field strength, μ is the magnetic permeability of the medium, n is the number of loops per unit length of the solenoid, and I is the current flowing through the solenoid.
Since the question states that solenoid 1 is sufficiently far from its ends, we can assume that the magnetic field inside the solenoid is uniform in magnitude and direction. Therefore, the magnitude of the magnetic field due to the current i1(t) in solenoid 1 is:b1(t) = μn1i1(t)