# The time taken by an electron placed in an electric field 1.2*1.^-5V/m to travel 20mm from rest

Balaji
13 Points
4 years ago
I can't get the question . Is 1.2 x 10↑-5 the electric field intensity?
If every thing is given then what to find in k,q,r,E.

Khimraj
3007 Points
4 years ago
acceleration of electron will be qE/m
and time taken to travel distance d will be
from second equation of motion
d = ½(qE/m)t2
So
t = $\sqrt{2dm/qE}$
Put value of d, m, q and E ang get answer