Question

Lines of force are imaginary,can they have any pratical use?​

Answer 1

Answer:

The direction of this force can be represented by the imaginary lines. these imaginary lines are called electric lines of force... Therefore, the two opposite charges get attracted. hope it will help you ...

Answer 2

Answer:

We have,

ABCD as the cyclic quadrilateral in which the diagonal AC and BD.

intersect each other at point P.

also, given that,

AB=8cm,

CD=5cm

Now,

In ΔDCA and ΔAPB,

We have

∠DCP=∠ABP

∠CDP=∠PAB

Hence, 

ΔDPC∼ΔAPB (by A.A property)

According to the given question,

arΔAPBarΔDPC=(ABDC)2

⇒24arΔDPC=(85)2

⇒24arΔDPC=6425

⇒arΔDPV=6425×24

arΔDPC=9.375cm2