Question

What is magnitude and direction of electric field will balance an electron?

Answer 1

Weight is balanced by the force resulting from the E field's effect on the charge.  

F = EQ = weight = mg  

E = mg/Q  

You're given m and Q for each particle and you know g, so go for it. The force must be upward, which means the field should be upward for the proton and downward for the electron.

Answer 2

Answer:

What are the magnitude and direction of the electric field that will balance the weight of the following?

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For an electron/proton we use the equation qE=mg. Therefore the answer for magnitude would just to multiply the mass of an electron/proton by 9.8.