Question

Calculate the potential at a point P due to a charge of 4 x 10-7 C located 9 an

away, (ii) Hence obtain the work done in bringing a charge of 2 x 10-9 C from

infinity to the point P. Does the answer depend on the path along which the

charge is brought ?​

Answer 1

Answer:

The potential at a point P is due to a charge of 4 * 10^-7 C which is at a distance of 9m from the charge is 400J/C, the work  required in bringing a charge of 2 * 10^-9 C from infinity to P is $8*10^{-7}J$

Explanation:

• The potential due to a charge (q) at a distance (r) from it is given by the formula   $V=Kq/r$

From the question, we have

the charge $q=4*10^{-7}C$

distance to the point P $r=9m$

⇒ the potential at that point $V=\frac{9*10^{9}*4*10^{-7} }{9} =400J/C$

• The work done to  bring a charge from infinity is nothing but the product of potential at that point and charge $W=Vq$

we have given that

the charge is $q=2*10^{-9}C$

potential at that point is calculated as $V=400J/C$

⇒ work done $W=400*2*10^{-9} =8*10^{-7}J$

The work done do not depend on the path followed