Ask Questions, Get Answers

Want to ask us a question? Click here
Browse Questions
0 votes

Four point charges $\;+8 \mu C\;,-1 \mu C\;,-1 \mu C\;and\;+8 \mu C\;$ are fixed at the points $\;-\sqrt{\large\frac{27}{2}} m \;,- \sqrt{\large\frac{3}{2}} m \;,+ \sqrt{\large\frac{3}{2}} m \;and\;+\sqrt{\large\frac{27}{2}} m\;$ respectively on the Y-axis . A particle of mass $\;6\times10^{-4} kg\;$ and charge $\;0.1 \mu C \;$ moves along the - X direction . It's speed at $\;x=+ \infty\;$ is $\;V_{0}\;. \quad \;$ Answer the following question based on the passage. Kinetic energy of the particle at origin would be

$(a)\;3\times10^{-4} J \qquad(b)\;2.6\times10^{-4} J\qquad(c)\;2\times10^{-4} J\qquad(d)\;1.5\times10^{-4} J$

Can you answer this question?

1 Answer

0 votes
Answer : (b) $\;2.6\times10^{-4} J$
Explanation :
Potential at origin is
$V_{0}=1.8\times10^{4}\;[\large\frac{8}{3 \sqrt{\large\frac{3}{2}}}-\large\frac{1}{\sqrt{\large\frac{3}{2}}}]$
$V_{0}=3\times10^{4} \sqrt{\large\frac{2}{3}}$
$V_{0} \approx 2.44\times10^{4}$
Let T be the kinetic energy of the particle at origin .
Applying energy conservation at x=0 and at $\;x=\infty$
$T+q_{0} V_{0}=\large\frac{1}{2} mV_{0}^{2}$
$T=\large\frac{1}{2}\;m V_{0}^{2}-q_{0}V_{0}$
$T=2.6\times10^{-4} J\;.$
answered Feb 19, 2014 by yamini.v

Related questions

Ask Question
student study plans
JEE MAIN, CBSE, AIPMT Mobile and Tablet App
The ultimate mobile app to help you crack your examinations
Get the Android App