Charge is placed on two conducting spheres that are very far apart and connected
ID: 2128827 • Letter: C
Question
Charge is placed on two conducting spheres that are very far apart and connected by a long thin wire. The radius of the smaller sphere is 5 cm and that of the larger sphere is 12 cm. The electric field at the surface of the larger sphere is 810 kV/m. Find the surface charge density on each sphere.
Explanation / Answer
given both spheres are connected by wire
hence they will have same potential
so if q1,q2 are respective charges then q1/r1 = q2/r2
now for larger sphere electric field = 810kV/m = sigma1/epsilon
so sigma1 = 7.172 uc/m^2(charge density on larger sphere)
sigma1/sigma2 = q1/r1^2 * r2^2/q2 = r2/r1 = 5/12
so sigma2 = 12/5 * sigma1 = 17.213 uC/m^2