Electro-Magnetic Interference Practice Level - 1 - Class 12 MCQ

A metal disc of radius 100 cm is rotated at a constantangular speed of 60 rads^-1 in a plane at right angles toan external field of magnetic induction 0.05 Wbm^-2. Theemf induced between the centre and a point on the rimwill be

Near a circular loop of conducting wire as shown in the figure an electron moves along a straight line. The direction of the induced current if any in the loop is

An inductor having coefficient of self induction 40 mH.What is the energy stored in it when a current of 2 A ispassed through it?

Magnetic flux linked with a coil is Ø = 5t² + 2t + 3,wheret is second and Ø is in weber. At time t = 1 s, the valueof induced emf in volt.

A coil has self inductance L = 0.04 H andresistance R = 12Ω, connected to 220 V, 50 Hz supply,what will be the current flow in the coil?

Two similar circular loops carry equal currents in thesame direction. On moving coils further apart, the electriccurrent will

Energy associated with a moving charge is due to

A conducting rod of lenghi is moving in a transversemagnetic field of strengh B with velocity v. The resistanceof the rod is R. The current in the rod is

Three solenoid coils of same dimension, same numberof turn and same number of layers of winding are taken.Coil 1 with inductance L₁ was wound using a Mn wire ofresistance 11Ωm^-1 , Coil 2 with inductance L₂ was woundusing the similar wire but the direction of winding wasreversed in each layer, Coil 3 with inductance L₃ waswould using s superconducting wire. The self-inductanceof the coil L₁, L₂, L₃ are

Lenz's law of electromagnetic induction correspondsto the

A conducting circular loop is placed in a uniformmagnetic field of induction B tesla with its plane normalto the field. Now the radius of the loop starts shrinking at the rate

. Then the induced emf at the instantwhen the radius is r, is

If coil is open then L and R become

According to Lenz's law of electromagnetic induction

Whenever a magnet is moved either towards or awayfrom a conducting coil, an emf is induced, the magnitudeof which is independent of

Consider the statements :(i) If magnetic field, B = 0, then magnetic flux is also zero.(ii) If magnetic flux,f Ø= 0 , then magnetic field is also zero.

A rectangular coil ABCD which is rotated at a constantangular velocity about an horizontal as shown in thefigure. The axis of rotation of the coil as well as themagnetic field B are horizontal. Maximum current willflow in the circuit when the plane of the coil is

There are two solenoids of same length and inductance L but their diameters differ to the extent that one can just fit into the other. They are connected in three different ways in series. (1) They are connected in series but separated by large distance, (2) they are connected in series with one inside the other and senses of the turns coinciding, (3) both are connected in series with one inside the other with senses of the turns opposite as depicted in figures 1, 2 and 3 respectively. The total inductance of the solenoids in each of the case 1.2 and 3 are respectively

Two coils are placed close to each other. The mutualinductance of the pair of coils depends upon

The net magnetic flux through any closed surface, keptin a magnetic field is

​A simple pendulum with bob of mass m and conductingwire of length L swings under gravity through anangle 2 θ . The earth's magnetic field component in thedirection perpendicular to swing is B. Maximum potentialdifference induced across the pendulum is

Two identical induction coils each of inductance L joinedin series are placed very close to each other such thatthe winding direction of one is exactly opposite to thatof the other, what is the net inductance?

A horizontal rod of length L rotates about a vertical axiswith a uniform angular velocity ω . A uniform magnetic field B exists parallel to the axis of rotation. Then potential difference between the to ends of the rod is