A uniformly charged ring of radius 3a and total charge q is placed in xy-plane centred at origin. A point charge q is moving towards the ring along the z-axis and has speed u at z = 4a. The minimum value of u such that it crosses the origin is :
Options

Question

A uniformly charged ring of radius 3a and total charge q is placed in xy-plane centred at origin. A point charge q is moving towards the ring along the z-axis and has speed u at z = 4a. The minimum value of u such that it crosses the origin is :

Options

G1 Physics · Accepted Answer

Step 1: Identify the relevant electrostatic principle—Coulomb's law, superposition, Gauss's law, potential-energy conservation or conductor boundary conditions. Step 2: Write the corresponding equation using the quantities in the question and simplify the geometry. Step 3: Substitute the given values and compare with the alternatives. Final: Option B. In this specific setup, apply the calculation to: A uniformly charged ring of radius 3a and total charge q is placed in xy-plane centred at origi…