The magnetic force acting on a charged particle of charge -2 μ C in a magnetic field of 2 ~T acting in y direction, when the particle velocity is (2 i +3 j ) × 10^6 ~ms^ -1 is

NEET 2009

NEET 2009 · Physics · Magnetic Effects of Current

The magnetic force acting on a charged particle of charge -2 μ C in...

The magnetic force acting on a charged particle of charge

-2 \mu \mathrm{C}

in a magnetic field of

2 \mathrm{~T}

acting in

y

direction, when the particle velocity is

(2 \hat{\mathrm{i}}+3 \hat{\mathrm{j}}) \times 10^6 \mathrm{~ms}^{-1}

A. $8 \mathrm{~N}$ in $-\mathrm{z}$ direction

Key Idea: When a charge q moves with velocity

\vec{v}

inside magnetic field of strength

\overrightarrow{\mathrm{B}}

, then force on charge is called magnetic Lorentz force. The magnetic Lorentz force is in the direction of vector

\overrightarrow{\mathrm{v}} \times \overrightarrow{\mathrm{B}}

\begin{aligned} & \text{ Magnetic Lorentz force } \overrightarrow{\mathrm{F}}=q(\overrightarrow{\mathrm{v}}\times \overrightarrow{\mathrm{B}}) \\ &=-2 \times 10^{-6}\left[2 \times 2 \times 10^6\right] \\ &=8 \mathrm{~N} \text{ along negative -axis } \end{aligned}