Excess electrons or protons on drop.

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Homework Help Overview

The discussion revolves around a physics problem involving a small water drop suspended in an electric field. Participants are tasked with determining the number of excess electrons or protons on the drop based on its charge and the electric field strength.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants are sharing their calculations and expressing uncertainty about their results, particularly regarding the charge of the drop and the method used to calculate the number of excess electrons or protons. There is a focus on whether the charge was divided or multiplied by the charge of an electron.

Discussion Status

There is an ongoing exploration of the calculations involved, with participants questioning each other's approaches and results. Some guidance is offered regarding the potential misunderstanding of the mathematical operations involved, but no consensus has been reached on the correct answer.

Contextual Notes

Participants are working with specific values provided in the problem statement, and there seems to be confusion regarding the application of formulas and the interpretation of results. The original poster's calculations are noted to be significantly different from others, indicating possible errors in their approach.

rcmango
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Homework Statement



A small drop of water is suspended motionless in air by a uniform electric field that is directed upward and has a magnitude of 8450 N/C. The mass of the water drop is 3.80 10-9 kg.

(b) How many excess electrons or protons reside on the drop?






Homework Equations





The Attempt at a Solution



i'm not sure what I'm doing wrong, but i get about 4.1071 x 10^-12 C

and for the drops i get 2.754 x 10-31

not sure why its wrong?

i used this for formula, see image: http://img180.imageshack.us/img180/6734/80350082pv3.png
 
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I'm not sure what you're asking here really. I presume the image is the answer to the question and you're wondering why yours is different. From the 2.754x10-31 it appears you've multiplied the charge on the drop by that on a proton.
 
well the image has different values to be calculated, and the image was just another example to show what was going on,

the problem i calculated was different, but it should still be calculated the same.

and it should be: 2.75e+07 but not sure why?
 
i'm not sure what I'm doing wrong, but i get about 4.1071 x 10^-12 C

and for the drops i get 2.754 x 10-31

not sure why its wrong
I'm getting slightly different numbers than you, but are you sure you're dividing by the electron charge and not multiplying? That's the only way I can see you getting an answer with that magnitude.
 

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