A particle of specific charge ' α ' is moving with velocity V 0 at t = 0 , on a rough horizontal floor and the coefficient of friction is μ . A uniform magnetic field B, directed verticall

Question

A particle of specific charge ' α ' is moving with velocity V 0 ​ at t = 0 , on a rough horizontal floor and the coefficient of friction is μ . A uniform magnetic field B, directed vertically downwards is also switched on at t = 0 . Find out the INCORRECT statements out of the following.

TestHub · Accepted Answer

Speed reduces due to friction, so radius of curvature $r = \frac{m v}{Bq}$ keeps decreasing ⇒ path is a spiral, not an ellipse ⇒ (A) is INCORRECT.

Magnetic force does no work; work-energy theorem: $- μ m g S = 0 - \frac{1}{2} m V_{0}^{2} \Rightarrow S = \frac{V _{0}^{2}}{2 μg}$ = total DISTANCE (path length).

Displacement is not equal to this path length ⇒ (B) is INCORRECT, (C) is correct.

Incorrect statements: (A) and (B).

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Options:(select one or more)

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