Whats is $\frac{e}{m}$ value for electrons ?

$\frac{e}{m}$ value for electron is the ratio of charge on an electron to its mass.

Charge on an electron = 1.602 $\times$ ${10}^{-19}$ C.

Mass of an electron = 9.109 $\times$ ${10}^{-31}$ Kg.

Therefore,

$\frac{e}{m}$ = $\frac{1.602\times {10}^{-19}C}{9.109\times {10}^{-31}Kg}$

$\Rightarrow$ $\frac{e}{m}$ = $\frac{1.602\times {10}^{-19}C}{9.109\times {10}^{-31}Kg}$

$\Rightarrow$ $\frac{e}{m}$ = 1.76 $\times$ ${10}^{11}$ C/kg