A cylindrical bar magnet is held along the axis of a circular conducti...
A cylindrical bar magnet is kept along the axis of a circular coil. If the magnet is rotated about its axis, then there is no change in magnetic flux, there is no emf induced in the coil, no current will be induced in the coil.
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A cylindrical bar magnet is held along the axis of a circular conducti...
Explanation:
To understand why option 'A' is the correct answer, let's analyze the effects of each movement on the induction of current in the conducting loop.
a) The magnet is rotated about its own axis:
- When the magnet is rotated about its own axis, the magnetic field lines passing through the loop change, inducing an electromotive force (EMF) in the loop. This EMF causes a current to flow through the loop.
b) The magnet is moved along its length:
- When the magnet is moved along its length, the magnetic field passing through the loop changes, inducing an EMF in the loop. This EMF causes a current to flow through the loop.
c) The magnet is rotated about an axis passing through its midpoint and perpendicular to its length:
- When the magnet is rotated about an axis passing through its midpoint and perpendicular to its length, the magnetic field lines passing through the loop change, inducing an EMF in the loop. This EMF causes a current to flow through the loop.
d) The magnet is rotated about an axis through one end and perpendicular to its length:
- When the magnet is rotated about an axis through one end and perpendicular to its length, the magnetic field lines passing through the loop change, inducing an EMF in the loop. This EMF causes a current to flow through the loop.
As we can see, all movements of the magnet induce a current in the loop except when the magnet is rotated about its own axis. In this case, the magnetic field passing through the loop remains constant, and there is no change in the magnetic flux. Therefore, no EMF is induced in the loop, and no current flows through it.
Hence, option 'A' is the correct answer as rotating the magnet about its own axis does not induce a current in the conducting loop.