Posted by ~christina~ on Sunday, March 30, 2008 at 9:14am.
Two small silver spheres with a mass of 10.0g, are separated by 1.00m. Calcuate the fraction of the electrons in one sphere that must be transfered to the other to produce an attractive force of 1.00x10^4 N (about 1 ton) between spheres (number of electrons per atom of silver is 47, and the number of atoms per gram is avogadro's number divided by the molar mass of silver, 107.87g/mol.
Fe=ke(|q1|q2|)/r^2 =1.00x10^4 N
then
q1/(-1.6021765x 10^-19C)= ans/47= the fraction of e- transfered to the other sphere
I'm not sure how to find the q2 and I think I need to find q1 from the equation below (what would I put in for q2)?
Please help.
Thanks
I'm not what to put for q2 in the equation above to find q1 from the equation above (what would I put in for q2)?
I'm asking nicely. =D
(I can almost solve the problem if only someone could tell me what do I put into the force equation for q2 -pretty frustrating that I can "almost" solve it but I need just one part)
Since you are transfering charge from one sphere to the other, q1 = -q2. Let the absolute value of both be q and just solve for q. The force will be attraction since the charges are opposite in sign. Once you have q, divide it by e for the numnber of electrons. Compare that to the number of electrons in a 10 g silver sphere. Each sphere would have this number of elctrons: (10g/107.87g/mole)*47 elecrons/atom*6.02*10^23atoms/mole
do you mean that it would be
q1=-q2
Fe=ke|q1||-q1|/r^2= ke(2q)/r^2
No. The product of the two charge absolute values is q^2, not 2q.
okay. but why do you say to compare that to the number of electrons in a 10g silver sphere?
Because that is what the problems asks for -- a fraction. Read it again:
"Calculate the fraction of the electrons in one sphere that must be transfered to the other"
I was just telling you how to do it. It will probably be a very low fraction.
I got it drwls.
Thank you.
To find the value of q2, you need to rearrange the equation for the force between the two spheres and solve for q2. The equation is given as:
Fe = ke(|q1|q2|)/r^2
where Fe is the desired force, ke is Coulomb's constant, q1 and q2 are the charges on the two spheres, and r is the distance between them.
In this case, the desired force is given as 1.00x10^4 N. The value of ke is a constant equal to 8.99x10^9 Nm^2/C^2. The distance between the spheres, r, is given as 1.00m.
To solve for q2, rearrange the equation as:
q2 = (Fe * r^2) / (ke * |q1|)
Now you can substitute the known values into the equation to find q2. Be sure to use the appropriate units for each variable.