Question

An electron accelerated by 200 V , enters a magnetic field .If its velocity is 100 m/sec .then(e/m) for it will be:(C/Kg)

• A. $1.75\times {10}^{10}$
• B. $1.75\times {10}^{11}$
• C. $1.75\times {10}^9$
• D. $1.75\times {10}^6$

Answer 1

Answer: (B)

$1.75\times {10}^{11}$

Given,

$V=200V$

$v=100m/s$

$e=1.6\times {10}^{-19}C$

$m=9.1\times {10}^{-31}Kg$

$\frac{e}{m}=\frac{1.6\times {10}^{-19}}{9.1\times {10}^{-31}}$

$\frac{e}{m}=1.75\times {10}^{11}$

The correct option is B.