AP EAMCET Engineering 23 Sep 2020 Shift 1 Paper

As we know that, work done by the uniform electric field in moving a charge depends only on its final position and initial position.
Displacement of charged particle in uniform electric field, r=rS−rP
=(0

∧

i

+0

∧

j

+0

∧

k

)−(a

∧

i

+b

∧

j

+0‌

∧

k

)
=−a

∧

i

−b

∧

j

∴ Work done by electric field. W=∫F‌clec ‌⋅dr
Here, Fdec=qE=qE

∧

i

(which is uniform)
W=Fclec⋅∫dr=Felec⋅r
=(qE

∧

i

)⋅(−a

∧

i

−b‌

∧

j

)
W=−qEa