Electricity Homework: Solving 3 Questions

AI Thread Summary
The discussion revolves around three electricity homework questions regarding charge and electrical forces. The first question involves calculating the number of electrons removed from an insulator with a positive charge of 2.4 x 10^-17 C, which results in 150 electrons removed. The second question addresses how moving two protons three times farther apart reduces their electrical force to 1/9 of the original, while the third question states that moving them three times closer increases the force by a factor of 9. Participants suggest using Coulomb's law to understand these relationships, which helps clarify the application of the relevant equations. The user expresses gratitude for the guidance received in solving these problems.
Jp_Garant
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Homework Statement


Three questions in all. I am unable to find out HOW to get the answer with my textbook.
1. An insulator has a positive electric charge of 2.4 x 10^-17 C. How many electrons were added or removed? (^-17 means to the power of negative 17). The answer is 150 electrons removed. However, i am not sure how to get to this answer!

2.If two protons are moved 3 times father apart, the electrical force between them is what factor of the original force? The answer is 1/9. Again, no idea how to get that.

3.If two protons are moved 3 times closer together, the electrical force between them is what factor of the original force? Answer is 9 times greater... how? no idea.


Homework Equations


In my textbook, i have the following info: which may be used to find the answer, but i don't know how.

Electron------------Mass 9.11 x 10^-31kg-----------Charge -1.60 x 10^-19
Proton-------------Mass 9.673 x 10V-27-------------Charge 1.60 x 10^-19


The Attempt at a Solution



I have tried dividing the charge by 3 and also divding by 3.. as the question suggests factor of 3.. but it obviously doesn't work.. I am looking at some equations in the book.. some for current.. I=q/t.. but we have no "t" in these questions.. Pleae help! I would greatly appreciate, as i have an exam tomorrow! :)Thanks
 
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Jp_Garant said:
2.If two protons are moved 3 times father apart, the electrical force between them is what factor of the original force? The answer is 1/9. Again, no idea how to get that.

3.If two protons are moved 3 times closer together, the electrical force between them is what factor of the original force? Answer is 9 times greater... how? no idea.

Hi Jp_Garant! :smile:

For 2 and 3, look up Coulomb's law
 


Thankyou Tim! I am now able to use this.. tho I needed help... simply because i didnt know how to apply the math. Thankyou :)
 
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