State the principle of moving coil galvanometer?

Why earth's magnetic field does not affect the working of the moving coil galvanometer?

State the principle of optical pipe.

Why are pole pieces of.a moving coil galvanometer made concave ?

Why is the core of moving coil galvanometer laminated?

State two properties of the material of the wire used for suspension of the coil in a moving coil galvanometer?

Why can we not use the ordinary moving coil galvanometer for measureing a.c. current and voltage?