Explanation
As the north pole approaches, a north pole is developed at the face, i. e., the current flows anticlockwise. Finally when it completes the oscillation, no e.m.f. is present. Now south pole approaches the other side, 1. e., RI-IS, the current flows clockwise to repel the south pole. This means the current is anticlockwise at the LHS as before. The break occurs when the pendulum is at the extreme and momentarily stationary.
When ring enters and leaves the field polarity of induced e.m.f. is opposite. Also during the stay of ring completely in the field there is no induction.
When a metallic conductor is moved in a magnetic field; magnetic flux is varied. It disturbs the free electrons of the metal and sets up an induced e.m.f. in
As there are no free ends of the metal, i.e., it will be closed in itself so there will be induced current.
According to Faraday’s laws, the conversion of mechanical energy into electrical energy is in accordance with the law of conservation of energy. It is also clearly known that in pure resistance, the e.m.f. is in phase with the current,
Presence of magnetic flux cannot produce current.
If the wires arc twisted together, they can be formed as a single wire carrying currents in opposite directions. In this pattern, in wires no magnetic field is induced which does not affect adjacent circuits.
Since both the loops are identical (same area and number of turns) and moving with a same speed in same magnetic field. Therefore same e.m.f. is induced in both the coils. But the induced current will be more in the copper loop as its resistance will be lesser as compared to that of the aluminium loop.
The inductance coils made of copper will have very small ohmic resistance. Due to change in magnetic flux a large induced current will be produced in such an inductance coil which will offer appreciable opposition to the flow of current.
As the aircraft flies, magnetic flux changes through its wings due to the vertical component of the earth’s magnetic field. Due to this, induced e,m,f. is produced across the wings of the aircraft. Therefore, the wings of the aircraft will not be at the same potential.
According to Lenz’s law, induced e.m.f. are in a direction such as to attempt to maintain the original magnetic flux when a change occurs. When the switch is opened, the sudden drop in the magnetic field in the circuit induces an e.m.f. in a direction that attempts to keep the original current flowing. This can cause a spark as the current bridges the air gap between the poles of the switch. (The spark is more likely in circuits with large inductance).
Mutual inductance is the phenomenon according to which an opposing e.m.f. produces flux in a coil as a result of change in current or magnetic flux linked with a neighboring coil. But when two coils are inductively coupled, in addition to induced e.m.f. produced due to mutual induction, induced e.m.f. is also produced in each of the two coils due to self-induction.
Lenz’s law is based on conservation of energy and induced e.m.f. always opposes the cause of it, i.e., change in magnetic flux.
When the satellite moves in inclined plane with equatorial plane (including orbit around the poles), the value of magnetic field will change both in magnitude
and direction. Due to this, the magnetic flux through the satellite will change and hence induced currents Will be produced in the metal of the satellite. But no current Will induced if satellite orbits in the equatorial plane because the magnetic flux does not change through the metal of the satellite in this plane.
Efficiency of electric motor is maximum when the back e.m.f. set up in the armature is half the value of the applied battery e.m.f.
When a metal piece falls from a certain height then eddy currents are produced in it due to earth’s magnetic field. Eddy currents oppose the motion of piece. Hence metal piece falls with a smaller acceleration (as compared to g). But no eddy currents arc produced in non-metal piece. Hence it drops with acceleration due to gravity. Therefore non-metals piece will reach the earth’s surface earlier.
Transformer works on ac only, ac changes in magnitude as well as in direction.
Hysteresis loss in the core of transformer is directly proportional to the hysteresis loop area of the core material. Since soft iron has narrow hysteresis loop area, that is why soft iron core is used in the transformer.
ac generator is based on the principle of the electromagnetic induction. When a coil is rotated about an axis perpendicular to the direction of uniform magnetic field, an induced emf is produced across it.
With rise in current in coil A flux through B increases. According to Lenz’s law repulsion occurs between A and B.
Crosses (x) linked with the loop are decreasing, so induced current in it is clockwise, i. e., from B → A. Hence electrons flow from plate A to B so plate A becomes positively charged.
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