Question

Two point charges of 1 $\mu C$ and $- 1\mu C$ are separated by a distance of 100 $\overset{o}{A}$. A point P is at a distance of 10 cm from the midpoint and on the perpendicular bisector of the line joining the two charges. The electric field at P will be.

• A. $9NC^{- 1}$
• B. $0.9NC^{- 1}$
• C. $90NC^{- 1}$
• D. $0.09NC^{- 1}$

Answer 1

Answer: (B)

$0.9NC^{- 1}$

Answer 2

: The point lies on equatorial line of a short dipole.

$\therefore E = \frac{2ql}{4\pi\varepsilon_{0}r^{3}} = \frac{9 \times 10^{9} \times 10^{- 6} \times 10^{- 8}}{(10^{- 1})^{3}}$

= 0.09 N $C^{- 1}$