Outer cylinder of the coaxial non-conductor of radius ‘b’ is given a positive potential V relative to the inner cylinder of radius ‘a’ as shown in the figure (charge distribution is uniform). A charge q (mass = m) is set free with negligible velocity at the surface of the inner cylinder. Find the velocity (in m s⁻¹), when it hits the outer cylinder. [Consider V = 10, q = -20, m = 1 all in S.I. Units]

Question

G1 Physics · Accepted Answer

Step 1: The outer cylinder is at potential 10 V relative to the inner one. For q=-20 C moving from inner to outer, ΔU=qΔV=(-20)(10)=-200 J. Step 2: With negligible initial speed, ΔK=-ΔU=200 J. Step 3: ½mv²=200 with m=1 kg gives v=20 m s⁻¹.