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Question Number 40770 by Necxx last updated on 27/Jul/18

A n e l e c t r i c d i p o l e i s p l a c e d a t r e s t

i n a u n i f o r m e x t e r n a l e l e c t r i c

f i e l d, a n d r e l e a s e d . D i s c u s s i t s

m o t i o n m a t h e m a t i c a l l y .

Answered by tanmay.chaudhury50@gmail.com last updated on 27/Jul/18

l e t a n g l e b e t w e e n a x i s o f d i p o l e a n d e l e c t r i c

f i e l d i s θ

l e n g t h o g d i p o l e = 2 l c h a r g e o n e a c h p o l e a r e

+ q a n d - q e x t e r n a l e l e c t r i c f i e l d = E

s o n e t f o r c e o n d i p o l e = q E + (- q) E = 0

T o r q u e w i t h r e s p e c t t o c e n t r e o f d i p o l e i s

\vec{⌈} = \vec{l} \times q \vec{E} + (- \vec{l}) \times (- q \vec{E})

= 2 q \vec{l} \times \vec{E}

⌈ = 2 q l E s i n θ