Why the coil of a dead beat galvanometer is wound on a metal frame?

The number of turns of the coil of a moving coil galvanometer is n, the area enclosed by the coil is A and the magnetic field is B. Find how much torque will act on the coil if a current of strength I flows through that coil.

An electric cell of emf 2V and of negligible internal resistance is connected in series with a coil of resistance a 20 Omega and a galvanometer of resistance 200 Omega, a 20 Omega resistances is parallel with the galvanometer,find out the galvanometer current.

The magnets of two suspended coil galvanometer are of the same strength so that they produce identical uniform magnetic fields in the region of the coils. The coil of the first one is in the shape of a square of side a and that of the second one is circular of radius (a)/(sqrtpi) . When the same current is passed throught the coils, the ratio of the torque experienced by the first coil to that rxperienced by the second one is

With reference to where a small bar magnet M approaches a coil C (with ends connected to a galvanometer), show that, Lenz's law is consistent with the principle of conservation of energy. What will be the magnetic polarity of the coil according to the diagram, as the magnet moves through it and comes out from the left?

If the current sensitivity of a moving coil galvanometer is increased by 20% , its resistance also increased by 1.5 times. How will the voltage sensitivity of the galvanometer by affected?

Out of ammeter, voltmeter and galvanometer, which one has the lowest resistance and why?

The magnets of two suspended coil galvanometers are of the same strength so that they produce identical magnetic fields in the region of the coils. The coil of the first one is in the shape of a square of side a and that of the second one is circular of radius a// sqrt(pi) . when the same current is passed through the coils, the ratio of the torque experinced by the first coil to the experinced by the second one is

The resistance of a moving coil galvanometer is 500Omega and the current required for its maximum deflection is 10muA . To convert the galvanometer into a voltmeter to read a maximum voltage of 100 mV, what should be the resistance to be connected in series with it?