Which statement correctly distinguishes mutual inductance from transformer coupling?

Which statement correctly distinguishes mutual inductance from transformer coupling?

• A. Mutual inductance is a property of a single coil; transformer coupling uses two coils
• B. Mutual inductance is a property of two coils in a magnetic coupling; transformer coupling is a practical arrangement to transfer energy between primary and secondary with coupling coefficient k
• C. Mutual inductance only exists in DC devices; transformer coupling only in AC
• D. Mutual inductance is energy stored in the magnetic field; transformer coupling is energy transferred without losses

Answer: (B)