how does emf get induced when a rod is placed horizontally in horizontal plane of earths magnetic field

how does emf get induced when a  rod is placed horizontally  in horizontal plane  of earths magnetic field


1 Answers

25757 Points
5 years ago
The Earth's magnetic field can be broken down into two components: The vertical and the horizontal
Since the vertical component is parallel to the velocity, it's contribution to the Lorentz force on the electrons of the rod is zero, so we will concentrate only on the Horizontal Component
Consider a situation when the rod falls such that its length is perpendicular to the horizontal component of the Earth's magnetic field, that is assume the component is to the right, and one end of the rod is pointing towards you, and the other away from you
Assume the velocity of the rod is V downwards, the horizontal component of the Earth's magnetic field is Bh, charge on an electron is e
Now the electrons in the rod would experience a force eVBh in a direction away from you, and so the electrons will be accelerated and would accumulate at the end away from you, which will result in a positive charge at the end closer to you.
Thus an electric field would be induced, due to oppositely charged ends of the rod, which will result in an induced EMF
P.S. In the above scenario, it is of course assumed that the rod is  conducting and has mobile electrons .

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