Two short electic dipoles of moment P and 8P are placed in opposite direction on a line at a distance of 15cm. The electic will be zero at point between the dipoles wose distance from the dipole of moment P is

### Asked by KRISHPATEL.soc | 20th Jun, 2021, 02:02: PM

Expert Answer:

###
Electric field E due to a dipole at a distance r far away from its position is given as
E = K × [ ( 2 p ) / r^{3} ]
where K = 1/(4πε_{o} ) is Coulomb's constant and p is dipole moment .
Hence electric field of dipole at a far away distance is directly proportional to dipole moment
and inversely proportional to cube of distance .
As shown in figure, if A is a point which is at a distance r from a dipole of moment P and
at a distance (15-r) from another dipole of moment 8P in opposite direction ,
Then to get zero electric field at A , we have the condition
Above expression is simplified as , (15 - r ) = 2r or r = 5 cm

^{3}]

_{o}) is Coulomb's constant and p is dipole moment .

### Answered by Thiyagarajan K | 20th Jun, 2021, 03:15: PM

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