Electricity and Magnetism

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Moderate

Droplet in Equilibrium Hit by Electrons!

EANDM-VCWQTK

A charged drop of fluid of radius $R=5.9\ \mu m$ and density $\rho=950$ kg/m$^3$ is initially suspended in perfect equilibrium, immersed in a vertical, downward electric field of magnitude $E=5.0\times 10^6$ N/C. The drop is then hit by two electrons (of charge $-e=-1.60\times 10^{-19}\ {\rm C}$) , which are captured by the drop, as in the figure.

Created for Albert.io. Copyright 2016. All rights reserved.

Assuming the electric field still has the same value, and that the electrons have very low velocity when they hit the sphere, calculate the resulting initial acceleration of the drop.

A

$1.32\times 10^{3}\ {\rm m/s}^2$

B

$5.05\ {\rm m/s}^2$

C

$1.32\times 10^{-4}\ {\rm m/s}^2$

D

$1.96\ {\rm m/s}^2$