Question

Two small tiny conducting spheres, both initially having no charge, are brought into contact and given a total charge of 5.00x10^4 electrons. The spheres are then pulled apart until their centers are 12.0 cm apart. Assume the total number of electrons on the spheres remained the same as they were separated. a) what is the magnitude of the force that each sphere exerts on the other? b) Is the force attractive or repulsive?

Answer 1

Answer:

(A) $10^{-17}N$

(B) Repulsive force

Explanation:

We have given total charge on both spheres $=5\times 10^4electron$

Charge on 1 electron $=1.6\times 10^{-19}C$

So total charge $=5\times 10^4\times 1.6\times 10^{-19}=8\times 10^{-15}C$

Charge on both the sphere will be equally distributed

So charge on individual sphere $=\frac{8\times 10^{15}C}{2}=4\times 10^{1-5}C$

Distance between both the spheres = 12 cm = 0.12 m

According to coulombs law force between two charges is given by $F=\frac{1}{4\pi \epsilon _0}\frac{Q_1Q_2}{R^2}=\frac{KQ^2}{R^2}=\frac{9\times 10^9\times (4\times 10^{-15})^2}{0.12^2}=10^{-17}N$

(B) As the charge on both the sphere is of same sign so force will be repulsive