Question

A beam of ions enters normally into a uniform magnetic field of $4\times {10}^{-2}$ tesla with velocity of $2\times {10}^{5}m/s$. If the specific charge of the ion is $5\times {10}^{7}C/kg$, then the radius of the circular path described will be:

• A. 0.10 m
• B. 0.06 m
• C. 0.20 m
• D. 0.25 m

Answer 1

The correct option is A 0.10 m

Given $:\frac{e}{m}=5\times {10}^{7}C/kg$

In a cyclotron, radius of the circular path,

$r=\frac{mv}{Be}=\frac{2\times {10}^5}{5\times {10}^7\times 4\times {10}^{-2}}=0.1m$