Question

A particle of mass 2g and charge 1 mC is held at a distance of 1 metre from a fixed charge of 1 mC. If the particle is released, it will be repelled. The speed of the particle when it is at a distance of 10 metres from the fixed charge is-

• A. 100 m/s
• B. 90 m/s
• C. 60 m/s
• D. 45 m/s

Answer 1

Answer: (B)

90 m/s

Answer 2

Conserving energy

k = $\frac { 1 } { 2 }$ m₁ + k