Electromagnetic...

A uniform rod of resistance $$10\Omega$$ is bent into a ring of radius $$20\ cm$$. The ring is placed in a uniform magnetic field of induction $$2.0T$$ directed parallel to its plane. If ideal battery of emf $$5.0\ V$$ is connected between two points of the ring to obtain maximum force on the ring, then the value of this maximum force is

An e.m.f. of 5 volt is produced by a self inductance, when the current changes at a steady rate from 3 A to 2 A in 1 millisecond. The value of self inductance is

A metal disc rotates freely, between the poles of a magnet in the direction indicated. Brushes P and Q make contact with the edge of the disc and the metal axle. What current, if any, flows through R ?

Two concentric co-planar circular loops of radii $$r_1$$ and $$r_2$$ carry currents of respectively $$i_1$$ and $$i_2$$ in opposite directions (one clockwise and the other anticlockwise.) The magnetic induction at the centre of loops is half that due to $$i_1$$ alone at the centre. If $$r_2 = 2r_1$$. the value of $$i_2 / i_1$$ is 

A resistanceless conduct moves in uniform magnetic field on a uniform rectangular loop of resistance $$R$$ with constant velocity v moving from $$CD$$ to $$EF$$. Current through conduct 

Two inductance's connected in parallel are equivalent to a single inductance of $$1.5 \ H$$, and when connected in series are equivalent to a single inductance of $$8 \ H$$. The difference in their inductance is:- 

A long magnet moves with constant velocity along the axis of a fixed metal ring. It starts from a large distance from the ring, passes through the ring and then moves away far from the ring. The current in the ring is plotted against time. Which of the following best represents the resulting curve?

Flux linked through following coils changes with respect to time then for which coil an e.m.f. is not induced:

A conducting disc of radius R is rotating with angular velocity $$\omega $$.Mass of electron is and charged e. If electrons are the current carries in a conductor, the potential difference between the center and the edge of the disc is:

According to the faraday's laws of electro magnetic induction-