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In the above question find the force req...

In the above question find the force required to move the rod with constant velocity `v`, and also find the power delivered by the external agent.

Text Solution

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The force needed to keep the velocity constant
`F_(ext)=ilB=(B^(2)l^(2)v)/(R+r)`
Power due to external force `=(B^(2)l^(2)v^(2))/(R+r)=(epsi^(2))/(R+r)=i^(2)(R+r)`
Note that the power delivered by the external agent is joule heating in the circuit. That means magnetic field helps in converting the mechanical energy into joule heating.
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