Answer:
a) 800 keV
b) 24.996 km.
Explanation:
(a) we have
.............(1)
where,
= Change in kinetic energy
= charge of an electron
= Potential difference
also
.......(2)
E = electric field
d = distance traveled
Now from (1) and (2) we have,

substituting the values in the above equation, we get


Thus, the energy gained by the electron is <u>800 keV</u> if it is accelerated over a distance of 0.400 m.
(b) Using the equation (1), we have


or

or

Thus, to gain 50.0 GeV of energy the electron must be accelerated over a distance of<u> 24.996 km.</u>