Question

An infinite number of charges each of magnitude q are placed on x- axis at a distance of 1,2,4,8...meter from origin respectively.Find intensity of electric field at origin

Answer 1

Explanation:

We know E=

r

2

kq

Now electric field at 0=

1

2

kq

+

2

2

kq

+

4

2

kq

+

8

2

kq

+−−−−

=kq(1+

2

2

1

+

2

4

1

+

2

6

1

+−−−−)

We know in G. P sum to infinite =

1−r

a

=kq⋅(

1−

4

1

1

)

=

4πε

0

q

⋅

3

4

=

3πε

0

.

q

solution