Question

Two particles having same charge and KE enter at right angles into the same magnetic field and travel in circular paths of radil $2cm$ and $3cm$ respectively. The ratio of their masses is.

• A. $2:3$
• B. $3:2$
• C. $4:9$
• D. $9:4$

Answer 1

Answer: (C)

$4:9$

$\text{Given}:$$r_1=2cm$, $r_2=3cm$ $\text{Solution}:$ We know, $r=\frac{\sqrt{2mqV}}{qB}$ Hence, $\sqrt{\frac{2mV}{a{B}^2}}$ $\frac{r_1}{r_2}=\sqrt{\frac{m_1}{m_2}}$ $\frac{m_1}{m_2}=\frac{r_1^2}{r_2^2}$ Hence, $\frac{m_1}{m_2}=\frac{(2{)}^2}{(3{)}^2}=\frac{4}{9}$ $\text{Hence C is the correct option}$