(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

What is the escape speed of an electron launched from the surface of a 1.0-cm-diameter glass sphere that has been charged to 10nC?

2. Relevant equations

Given:

d= 1.0cm

r= 0.05cm= 0.0005m

q_{1}= 10nC = 10 x 10^{-9}(sphere)

q_{2}= -1.6 x 10^{-19}(electron)

Equation:

U = (kq_{1}q_{2})/r

KE= ½mv^{2}

3. The attempt at a solution

So, if the sum of kinetic and potential energy is supposed to be zero, then I get:

KE + U = 0

½m_{e}(v_{e})^{2}+ (kq_{1}q_{2})/r = 0

½(9.11 x 10^{-31})(v)^{2}+ ( (8.99 x 10^{9}) (10 x 10^{-9}) (-1.6 x 10^{-19}) ) / (0.0005) = 0

If I solve the above equation^^, I get v_{e}= 2.5 x 10^{8}m/s, which is incorrect. The correct answer is 8.0 x 10^{7}m/s. I am not sure what I am doing incorrectly, any help is appreciated. Sorry about the mess, I can't seem to figure out how to use TeX!

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# Homework Help: Electron Escape Speed

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