What is the mutual inductance of a pair of coils if current changing at the rate of 50 Ns in one coil induces an e.m.f of 50 mV in the other coil? What will be the secondary voltage produced by a...

What is the mutual inductance of a pair of coils if current changing at the rate of 50 Ns in one coil induces an e.m.f of 50 mV in the other coil?

What will be the secondary voltage produced by a transformer which has 400 primary turns and 100 secondary turns, when there is an alternating voltage input to the primary of 240 V?