Two point charges Q and – 3Q are placed at some distance apart. If the electric field at the location of Q is E then at the locality of – 3Q, it is nE. The value of n is

The field produced by charge – 3Q at A, this is E as mentioned in the Example.∴ E=3Qx2 (along AB directed towards negative charge)Now field at location of – 3Q i.e. field at B due to charge Q will be E'=Qx2=E3 (along AB directed away from positive charge)