Networks Analysis and Synthesis - Engineering

Q1:

A coil is wound having a diameter d. Its inductance is 10 mH. If it is rewound on the same core with a wire having diameter 0.5 d and total weight of the wire is the same as before, the inductance will be

A 5 mH

B 10 mH

C 160 mH

D 40 mH

ANS:C - 160 mH

Since diameter is halved, area of cross-section is one-fourth. The number of turns becomes four times. Inductance = μ N2.