Question

An $\alpha$-particle moving perpendicularly to a magnetic field of $0.2$ wb/metre? experiences a force of $3.84 \times 10^{-24} N$. Then speed of $\alpha$ particle will be :

• A. $ 6\times 10^{5}\,m/s $
• B. $ 5\times 10^{-5}\,m/s $
• C. $ 1.2\times 10^{6}\,m/s $
• D. $ 3.8\,\times 10^{6}\,m/s $

Answer 1

Answer: (A)

$q _{\alpha}=2 e =2 \times 1.6 \times 10^{-19}$
$F = qv \beta$
$\left(3.89 \times 10^{14}\right)=\left(3.2 \times 10^{-19}\right)_{ v }(0.2)$
$V =6 \times 10^{+33} m / sec$