question_answer

  A particle of mass 40 mg and carrying a charge \[5\times {{10}^{-9}}\] C is moving towards a fixed charge of magnitude \[{{10}^{-8}}\] C. When it is at a distance of 10 cm from the fixed charge, it has a velocity of 50 cm/s. At what distance from the fixed charge will the particle come momentarily to rest?

A)  \[1.3\,\times {{10}^{-3}}\,\,\,m\]          

B)  \[1.9\,\times {{10}^{-3}}\,\,\,m\]

C)  \[3.9\,\times {{10}^{-2}}\,\,\,m\] 

D)  \[4.7\,\times {{10}^{-2}}\,\,\,m\]