Answer to Question #166825 in Optics for aljohara

Question

what electrostatic force would exist between a point charge with a charge of 5.35x10 -7C and a second point charge with a charge of -7.73x10 -6C if the two charges were separated by a distance of 4.11x10 -2?

Answer 1

Here,

$q_1=5.35\times10^{-7}C$

$q_2=-7.73\times10^{-6}C$

$d=4.11\times 10^{-2}m$

For electrostatic force, $F_E= k\dfrac{q_1 q_2}{d^2}$

and $k = 9\times 10^9 Nm^2/C^2$

So, $F_E=(9\times 10^9\dfrac{Nm^2}{C^2})\dfrac{(5.35\times10^{-7}C)(-7.73\times10^{-6}C)}{(4.11\times10^{-2}m)^2}$

$=\dfrac{-372.1995}{16.8921}=-22.03N$

So, magnitude of electrostatic force $|F_E|=$ 22.03N

and negative sign shows that there is attraction between the two point charges.