A dipole is placed in an electric field as shown. In which direction will it move? (a) towards the right as its potential energy will increase. (b) towards the left as its potential energy will increase. (c) towards the right as its potential energy will decrease. (d) towards the left as its potential energy will decrease.

Answer: (c). +q-qqE (strong)qE (weak)E Lines spread out to the right, so E is stronger on the left, at +q. Force on +q (rightward, larger) exceeds force on -q (leftward, smaller): net force to the right. p (from -q to +q) is opposite to E, so U = -p = +pE; moving right E falls, so U decreases. So the answer is (c) towards the right as its potential energy will decrease.

A dipole is placed in an electric field as shown. In which direction… | NEET 2021

Q53NEET 2021Easy

Electric Dipole

A dipole is placed in an electric field as shown. In which direction will it move?

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Answer: (c)

Lines spread out to the right, so $E$ is stronger on the left, at $+q$ .
Force on $+q$ (rightward, larger) exceeds force on $-q$ (leftward, smaller): net force to the right.
$\vec{p}$ (from $-q$ to $+q$ ) is opposite to $\vec{E}$ , so $U = -\vec{p}\cdot\vec{E} = +pE$ ; moving right $E$ falls, so $U$ decreases.
So the answer is (c) towards the right as its potential energy will decrease.

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