# Physics - important

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An electron is accelerated through a uniform electric field of magnitude 2.5x10^2 N/C with an initial speed of 1.2x10^6 m/s parallel to the electric field.

a) Calculate the work done on the electron by the field when the electron has travelled 2.5 cm in the field.
b) Calculate the speed of the electron after it has travelled 2.5 cm in the field.
c) If the direction of the electric field is reversed, how far will the electron move into the field before coming to rest?

• Physics - important - ,

a) e E x
b) Assume the work done (above) equals the increase in kinetic energy
c) It will travel until
E e x = intial kinetic energy

• Physics - important - ,

Should the answer for B be 1.5x10^6 m/s because my book says it's wrong...

• Physics - important - ,

Oh, and what do you mean by 'x'?

• Physics - important - really confused - ,

Also, is there a final kinetic energy? I'm just really confused by this...

• Physics - important - ,

Won't the kinetic energies for question b and c be the same?