A point charge of 100 μC is placed at 3i^+4j^m. Find the electric field intensity due to this charge at a point located at 9i^+12j^m.

(2)r→A=3i^+4j^m,   r→B=9i^+12j^m∴   r→B/A   =    r→B −  r→A  =  6i^+8j^m  ⇒   r→B/A  = 62+82=10m∴    EB=14πε0   Qr→B/A 2=  9×  109 ×  100  ×  10−6102  V/m=9000 V/m