A 7uF capacitor is charged to a potential difference of 110V The electrical energy stoed in the capacitor is

Question

(4.2x10^-2 was the given answer)
but I used C=Q/V and keep getting 7.7x10^-4

also A particle of charge Q and mass m is accelerated from rest through a potential difference V, attaining kinetic energy K. What is the kinetic energy of a particle of charge 2Q and mass m/2 that is accelerated under the same conditions? (Answer was given as 2K but i got 4k)

Answer 1

W = 0.5CV^2,
W=0.5 * 7*10^-6 * (110)^2 = 4.23*10^-2.