JIPMER2010PhysicsMagnetic Effects of Current
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 magnetic field B . If speed of the electron is doubled and the magnetic field is halved, then resulting path would have a radius of
Options
- Ar 4
- Br 2
- C2 r
- D4 r
Correct answer
D. 4 r
Step-by-step solution
In a perpendicular magnetic field, Magnetic force = centripetal force ie, aligned & B q v= m v^2 r r= m v B q & r₁ r₂ = v₁ v₂ B₂ B₁ & r₁ r₂ = 1 2 1 2 & r₂=4 r₁ & r₂=4 r & aligned