An electron accelerates across a potential difference of 200

An electron accelerates across a potential difference of 200 volts. What energy does the electron gain? Assuming the electron starts at rest, at what speed is it moving through the potential?

Solution

a)

kinetic energy gained,

KE = V*q

= 200*(1.6*10-19)

= 3.2*10^-17 J

b)

Now, KE = 0.5*m*v^2

where m = mass of electron = 9.1*10^-31 kg

So, 3.2*10^-17 = 0.5*(9.1*10^-31)*v^2

So, v = 8.39*10^6 m/s <-----answer