An electron of mass m and charge q is travelling with a speed v along a circular path of radius r at right angles to a uniform of magnetic field B. If speed of the electron is doubled and the magnetic field is halved, then resulting path would have a radius of ____ .

An electron of mass m and charge q is travelling with a speed v along

1.	An electron of mass m and charge q is travelling with a speed v along a circular path of radius r at right angles to a uniform of magnetic field B. If speed of the electron is doubled and the magnetic field is halved, then resulting path would have a radius of ____ .
Answer» `R/4` `r/2` 2r 4r Solution :For the charge moving in the plane PERPENDICULARLY to the plane of magnetic FIELD, `Bqv=(mv^(2))/rrArrr=(mv)/(qB)" If "v_(1)=2v`, and taking `B_(1)=B_(2)` The RADIUS of path `r_(1)=(2mv)/q^(B/2)=(4mv)/(qB)=4r`

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An electron of mass m and charge q is travelling with a speed v along a circular path of radius r at right angles to a uniform of magnetic field B. If speed of the electron is doubled and the magnetic field is halved, then resulting path would have a radius of ____ .

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