Question

║⊕QUESTION⊕║
The important thing is not to stop questioning. Curiosity has its own reason for existence.
↓
CLASS 12
PHYSICS
↑
How much work is required to move a dipole of dipole movement 2 * 10 ⁻⁷ from one point to another point along a straight line in uniform electric field of strength 4 * 10² N/C without acceleration?

Answer 1

Answer:

$\displastyle \sf{{\rightarrow (8\times10^{-5})\left|\cos \theta\right|^b_a}}$

Explanation:

$\displastyle \text{{We know ;}}\\\\\\\displastyle \sf{{dW = -PE \ \sin \theta}}\\\\\\\displastyle \text{{Integrating both side a to b we get :}}$

$\displaystyle{\int\limits_{a}^{b} dW = - \int\limits_{a}^{b}PE \sin \theta}$

$\displastyle \sf{{W=-PE\left|-\cos \theta\right|^b_a}}\\\\\\\displastyle \sf{{W=PE\left|\cos \theta\right|^b_a}}\\\\\\\displastyle \text{{Using given P and E here :}}$

$\displastyle \sf{{W=(2\times10^{-7}\times(4\times10^2)\left|\cos \theta\right|^b_a}}\\\\\\\displastyle \sf{{W=(8\times10^{-5})\left|\cos \theta\right|^b_a}}\\\\\\\displastyle \text{{Since distance is not provided :}}\\\\\\\displastyle \text{{Therefore, final answer is as:}}\\\\\\\displastyle \sf{{\rightarrow (8\times10^{-5})\left|\cos \theta\right|^b_a}}$

Answer 2

Answer:

ANSWER

If we take a point M on the X-axis as shown in the figure, then the net electric field is in X-direction.

∴ Option (a) is incorrect.

If we take a point N on Y-axis, we find net electric field along +X direction. The same will be true for any point on X-axis.

So, (c) is a correct option.

The work is calculated as:

W

∞to0

=q(V

∞

−V

0

)=q(0−0)=0

(b) is incorrect.

The direction of the dipole moment is from-:-ve to +ve and it is not along the X-axis. Therefore (d) is incorrect.