Answer: a) 2.5 * 10 ^6 N/C; b) 102.71* 10^6 m/s
Explanation: In order to explain this problem we have to use the following expressions:
E= V/d the relationship of the electric field and the voltage. d is the separation distance between the plates.
Also we know,
e*V= (m*v^2)/2 ; this means that the change in potencial energy is gained by the electrons and converted in kinetic energy.
v= (2*e*V/m)^1/2= (2*1.6*10^-19*30000/9.1*10^-31)^1/2=102.71 * 10^6 m/s