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A circular conducting loop of radius `r_(0)` and having resistance per unit length lamba as shown in the figure is placed in a magnetic field B which is constant in space and time. The ends of the loop are crossed and pulled in opposite directions with a velocity v such that the loop always remains circular and the radius of the loop goes on decreasing then A. Radius of the loop changes with r as `r=r_(0)-vt//pi`B. EMF induced in the loop as a function of time is `e=2Nv[r_(0)-vt//pi]`C. Current induced in the loop is `I=(Bv)/(2pilambda)`D. Current induced in the loop is `I=(Bv)/(pilambda)` |
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Answer» Correct Answer - A::B::D Perimeter is decreasing at a rate of 2v `d/(dt)(2pir)=2v Rightarrow(dr)/(dt)=v/pi` `:.r=(r_(0)-v/pit)` `phi=Bpir^(2)Rightarrowvarepsilon=|(-dphi)/(dt)|=B 2pi r(dr)/(dt)` `:.varepsilon=2Bpi(r_(0)-v/pit)v/pi=2Bv(r_(0)-v/pit)` `I=phi/R=(2Bvr)/(lambda.2pir)=(Bv)/(pilambda)` |
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