Q 12-02-023NEETJEE MainMedium
An electron is accelerated from rest through a potential difference of $200$ V. Its final speed is ($e/m = 1.76 \times 10^{11}$ C/kg)
Answer: (D) $8.4 \times 10^6$ m/s
$eV = \dfrac{1}{2}mv^2 \Rightarrow v = \sqrt{2\dfrac{e}{m}V} = \sqrt{2 \times 1.76 \times 10^{11} \times 200} \approx 8.4 \times 10^6$ m/s.
Solution by Sreeraj P, M.Sc Physics