
#1
Sep1904, 02:09 PM

P: 6

All right i have a simple problem but i just want to verify my results, so any help would be greatly appreciated. The problem is as follows:
7.1* 10^12 electrons are added to a body that already has a negative charge of 0.2uC(the u is micro 10^6). Calculate the final charge on this body. Now i have (7.1* 10^12)(1.602* 10^19) + (0.2* 10^6) which gave me 1.337 uC is this correct? 



#2
Sep1904, 02:32 PM

P: 6

whoops, i think it should have been:
(7.1* 10^12)( 1.602* 10^19) + (0.2* 10^6) which gave me 0.937 uC now im lost...please help. 



#3
Sep1904, 03:47 PM

P: 6

new info, 1C is equal to 6.24* 10^18 electrons




#4
Sep1904, 03:57 PM

P: 6

Calculate charge on a body(in Coulombs)
ok, formula should be:
(7.1* 10^12)/(6.24* 10^18) + (0.2*10^6) = 1.337 uC which is the same as the first result i got...... 0_o i am going to go with this one. is this correct? 



#5
Sep1904, 05:12 PM

Emeritus
Sci Advisor
PF Gold
P: 1,817

Check all of your negative signs. The problem states that the body already has a negative charge,
Your magnitude looks right, but the sign is wrong. [mod hat] Moving the thread to homework help. [/mod hat] 



#6
Sep1904, 05:40 PM

P: 6

Thanks you were right about the sign, it was supposed to be 1.337 uC
Also, sorry about the location of my topic i only put it there because the course i am taking is electrical engineering and there was a section that matched exactly. I just joined the forum and i already know i will be here every day to read up on the info i need. Thanks again for the help, i will keep all homework related problems here. 


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