Electricity and Magnetism Answers

In an induction coil , the coefficient of mutual inductance is 4 Henry . if a current of 5 ampere in the primary coil is cut off in 1/1500 sec , the emf at the terminals of the secondary coil will be (1) 15kV. (2) 60 kV (3) 10 kV. (4) 30 kV

A non-relativistic free electron has kinetic energy K. If its wavelength λ triples, it is kinetic energy is:

A wheel having mass m has charge +q and -q on diametrically opposite points. It remains in equilibrium on a rough inclined plane in the presence of vertical electric field E. The value of E is__.
Ans: mg/2q

A α-particle moves in a circle of radius 5.0*10^-2m in magnetic field of 2.0T. Find the speed of the α-particle.

The electrical field associated with a monochromatic beam becomes zero 1.2× 1000000000000000 times per second . Find the maximum kinetic energy of the photoelectrons when this light falls on a metal surface whose work function is 2.0ev (1) 0.24ev (2) 0.48 ev (3) 0.72 ev. (4) 0.96 ev

A positive 20mC charge is placed at the centre of a circle of radius 20 cm. If we move a positive 2mC charge once along the circumference of the circle, will any work be done in the process? Justify your answer.

The electric potential near an isolated positive charge is a) positive or b) negative

You have a 1.0-m-long copper wire. You want to make an
N-turn current loop that generates a 1.0 mT magnetic field at the
center when the current is 1.0 A. You must use the entire wire.
'What will be the diameter of your coil?

A charged sphere of mass 2g is freely suspended in an electric field vector 5*100000j N/C.
Calculate the number of excess charged particles in the sphere

The magnetic field midway between two parallel current carrying wires , carrying current I and 2I is B . If the current in the wire with current I is switch off , the magnetic field will become (1) B/3 (2) 2B (3)B/2 (4) B/4