Question

3. An infinite number of charges each of magnitude q are
placed on x - axis at distances of 1,2, 4, 8, ... meter from the
origin. The intensity of the electric field at origin is​

Answer 1

Answer:

We know E = kqr2 Now electric field at 0 = kq12 + kq22 + kq42 + kq82 + - - - - = kq (1 + 122 + 124 + 126 + - - - - ) We know in G. P sum to infinite = ...

Answer 2

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