Question

Two particles $A$ and $B$ having equal charges $+6\, C$, after being accelerated through the same potential difference, enter a region of uniform magnetic field and describe circular paths of radii $2\,cm$ and $3\, cm$ respectively. The ratio of mass of $A$ to that of $B$ is

• A. 44660
• B. 44809
• C. 44563
• D. 44564

Answer 1

Answer: (A)

44660

Answer 2

We have
$r= \frac {\sqrt {2mqV}}{qB}= \sqrt {\frac {2mV}{aB^2}}$
$\frac {r_1}{r_2}= \sqrt {\frac {m_1}{m_2}}$
$\frac {m_1}{m_2}= \frac {r_1^2}{r_2^2}$
Hence, $\frac {m_1}{m_2}= \frac {(2)^2}{(3)^2}= \frac {4}{9}$