Electrostatics Question 438
Question: A ball of mass 1 g and charge $ {{10}^{-8}}C $ moves from a point A. where potential is 600 volt to the point B where potential is zero. Velocity of the ball at the point B is 20 cm/s. The velocity of the ball at the point A will be [KCET 2001]
Options:
A) 22.8 cm/s
B) 228 cm/s
C) 16.8 m/s
D) 168 m/s
Show Answer
Answer:
Correct Answer: A
Solution:
By using $ \frac{1}{2}m(v _{1}^{2}-v _{2}^{2})=QV $
therefore $ \frac{1}{2}\times {{10}^{-3}}{v _{1}^{2}-{{(0.2)}^{2}}}={{10}^{-8}}(600-0) $
therefore $ v _{1}=22.8cm/s $
