QJEEM20Phaa2b: JEE Main 2020 Physics - Class 12 JEEM20Phaa2b Solution: A charged particle carrying charge 1 μ C is moving with…

Question

Verified Solution • 2025–26 Session moderate

A charged particle carrying charge 1

μ

C is moving
with velocity

(2 \hat{i} + 3 \hat{j} + 4 \hat{k})

ms^–1. If an external
magnetic field of

(5 \hat{i} + 3 \hat{j} - 6 \hat{k})

× 10^–3 T exists in the region where the particle is moving then the
force on the particle is

\vec{F}

× 10^–9 N. The vector

\vec{F}

is :

Accepted Answer

Given,

\vec{V}

=

(2 \hat{i} + 3 \hat{j} + 4 \hat{k})

ms^–1

\vec{B}

=

(5 \hat{i} + 3 \hat{j} - 6 \hat{k})

× 10^–3 T

q = 1

μ

C

\vec{F} = q (\vec{V} \times \vec{B})

=

10^{- 6} \times 10^{- 3} \times | \begin{matrix} \hat{i} & \hat{j} & \hat{k} \\ 2 & 3 & 4 \\ 5 & 3 & - 6 \end{matrix} |

= (

- 30 \hat{i} + 32 \hat{j} - 9 \hat{k}

)

\times

10^-9

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