QJEEM20Ph1507: JEE Main 2020 Physics - Class 12 JEEM20Ph1507 Solution: A particle of charge q and mass m is moving with a velocity − v …

Question

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A particle of charge q and mass m is moving with a velocity

- v \hat{i}

(v

\neq

0) towards a large screen placed in the Y - Z plane at a distance d. If there is a magnetic field

\vec{B} = B_{0} \hat{k}

, the maximum value of v for which the particle will not hit the screen is :

Accepted Answer

In uniform magnetic field particle moves in a circular path, if the radius of the circular path is 'd', particle will not hit the screen.

r =

\frac{m v}{q B_{0}}

To not collide, r < d

\Rightarrow

\frac{m v}{q B_{0}}

< d

\Rightarrow

v <

\frac{q B_{0} d}{m}

∴

v_max =

\frac{q B_{0} d}{m}

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