An electron having charge $1.6×10^{-19} C$ and mass $9×10^{-31} kg$ is moving with $4 × 10^6 m/s$ speed in a magnetic field $2×10^{-1} T$ in a circular orbit. The force experienced by the electron and the radius of the circular orbit, respectively will be :
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → $1.28 × 10^{-13} N, 1.1×10^{-4} m$
Using Lorentz force,
$F=qvB$
$=(1.6×10^{-19})(4 × 10^6)(2×10^{-1})$
$=1.28×10^{-13}N$
Radius of circular orbit (r),
$r=\frac{mv}{qB}=\frac{9×10^{-31}×4×10^6}{1.6×10^{-19}×2×10^{-1}}=1.1×10^{-4}m$