A wire in the form of a tightly wound solenoid is connected to a DC source and carrries a current .If the coil is stretched so that there are gaps between successive elements of the spiral coil,will the current increase or decrease ?Explain.

A solenoid is connected to a battery so that a steady current flows through it. If an iron core is inserted into the solenoid, will the current increase or decrease?Explain.

What change do we observe in the galvanometer if the current in the solenoid coil is increased?

A long solenoid consisting of 1.5xx10^3 turns//m has an area of cross-section of 25 cm^2 . A coil C, consisting of 150 turns (N_c) is wound tightly around the centre of the solenoid. Calculate for a current of 3.0 A in the solenoid (a) the magnetic flux density at the centre of the solenoid, (b) the flux linkage in the coil C, (c) the average emf induced in coil C if the current in the solenoid is reversed in direction in a time of 0.5 s. (mu0=4pixx10^-7 T.m//A) .

A closely wound flat circuar coil of 25 turns of wire has diameter of 10 cm which carries current of 4 A , the flux density at the centre of a coil will be

Two coils are connected in series in one gap of metre bridge and null point is obtained at the middle of wire by putting 50 ohm resistance in other gap. The two coils are then connected in parallel and it is found that resistance in the other gap has to be decreased by 38 Omega to get the null point at same place as before. Find the resistance of each coil

A 10 muF capacitor is charged to a 25 volt of potential.The battery is disconnected and a pure 100 mH coil is connected across the capacitor so that LC oscillations are set up. Calculate the maximum current in the coil.