A small particle of mass and charge is projected directly away from a fixed positive…

PHYSICS · Single correct · CBSE · Physics · Electrostatic Potential and Capacitance · Electrostatic Potential and Capacitance

Problem

A small particle of mass

m

and charge

-q

is projected directly away from a fixed positive charge

+Q

with speed

v_0

from an initial separation

r_0

. Neglecting all forces except the mutual electrostatic interaction, which expression gives the minimum value of

v_0

that will allow the particle to reach an infinite distance from

+Q

? (a)

v_0 = \sqrt{\dfrac{kQq}{m r_0}}

(b)

v_0 = \sqrt{\dfrac{2kQq}{m r_0}}

(c)

v_0 = \sqrt{\dfrac{kQq}{2m r_0}}

(d)

v_0 = \sqrt{\dfrac{4kQq}{m r_0}}