Two particles having positive charges +Q and +2Q are fixed at equal distance x from the center of a conducting sphere having zero net charge and radius r as shown. Initially, switch S is open. After switch S is closed, the net charge flowing out of the sphere is:

Explanation

When switch S is closed, the conducting sphere becomes influenced by both charges +Q and +2Q. The sphere induces a charge on its surface to maintain electrostatic equilibrium. By the principle of superposition, the net charge induced on the surface of the sphere will be the sum of the charges induced by both +Q and +2Q individually. Here, the charge induced is proportional to the sum of the charges, resulting in 3Qr/x flowing out of the sphere. Therefore, Option C is correct.Option A and B underestimate the charge flow by considering only partial influences, while Option D overestimates the effect due to miscalculation or duplication of factors.