Question

Two iron spheres are suspended from strings and

separated by a distance of 9.0 meters. The
charge on one sphere is 7.0*10^-8 Cand the other -3.0
*10^-5 C. What is the electric force on the spheres?
A. A repulsive force of 4.6*10^-4N
B. An attractive force of 2.3*10^-4 N
C. An attractive force of 4.6*10^-4 N
D. A repulsive force of 2.3*10^-4 N​

Answer 1

B. An attractive force of 2.3*10^-4 N

Step-by-step explanation:

As we know by Coulomb's law that the electrostatic force between two charges is given as

`F = (kq_1q_2)/(r^2)`

here we know that

`q_1 = 7 * 10^(-8) C`

`q_2 = -3 * 10^(-5) C`

r = 9.0 m

now we have

`F = ((9 * 10^9)(7 * 10^(-8))(3* 10^(-5)))/(9^2)`

`F = 2.3 * 10^(-4) N`

since both charges are opposite charges so they will attract each other by the force we calculated above so correct answer will be

B. An attractive force of 2.3*10^-4 N