Posted: 9/25/2014 1:24:37 AM EDT
|
Trying to help my son figure this out.
Two charges are separated by a distance of 0.5 m. Charge Q1 = -9 µC. The electric field at the origin is zero. a.What is the magnitude and sign of charge Q2? b.What is the magnitude and direction of the electric force between the charges? c.What is the electric energy of the system of two charges? d.What is the net electric potential at the origin? e.How much work is required to bring a negative charge of -1 nc from infinity to the origin? |
|
Quoted:
Trying to help my son figure this out. Two charges are separated by a distance of 0.5 m. Charge Q1 = -9 µC. The electric field at the origin is zero. a.What is the magnitude and sign of charge Q2? b.What is the magnitude and direction of the electric force between the charges? c.What is the electric energy of the system of two charges? d.What is the net electric potential at the origin? e.How much work is required to bring a negative charge of -1 nc from infinity to the origin? I have to make some assumptions because I do not have the picture that goes with this problem. Assuming that the charges are equal distance from the origin ie .25m.... k=1/(4*E0*pie)=9*10^9 a) Electric field add up. So the elctric field caused by Q1 at the origin is E=k(-9uC)/.25^2=-1294819.876V/M. Well Since we know that the E field is 0 and that the fields add up, we can use the formula 1294819.876V/M=kQ2/.25^2. We have to use a positive value because those 2 values added up will make the E field zero. So surprise surprise, the charge is equal but opposite. +9uC. Which should make sense. b) F=KQ1Q2/R^2=k*9uC*9uC/.25^2=11.65N Be sure when you actually write this out to put in units and show cancellations. c) I think they mean potential energy? Im not sure on this one. But its U=kQ1Q2/r = .324 N/m d) Net electric potential was figured in problem a. Its 0 since the electric field is 0. e) I don't feel like doing any integration |
|
Quoted:
I have to make some assumptions because I do not have the picture that goes with this problem. Assuming that the charges are equal distance from the origin ie .25m.... k=1/(4*E0*pie)=9*10^9 a) Electric field add up. So the elctric field caused by Q1 at the origin is E=k(-9uC)/.25^2=-1294819.876V/M. Well Since we know that the E field is 0 and that the fields add up, we can use the formula 1294819.876V/M=kQ2/.25^2. We have to use a positive value because those 2 values added up will make the E field zero. So surprise surprise, the charge is equal but opposite. +9uC. Which should make sense. b) F=KQ1Q2/R^2=k*9uC*9uC/.25^2=11.65N Be sure when you actually write this out to put in units and show cancellations. c) I think they mean potential energy? Im not sure on this one. But its U=kQ1Q2/r = .324 N/m d) Net electric potential was figured in problem a. Its 0 since the electric field is 0. e) I don't feel like doing any integration Quoted:
Quoted:
Trying to help my son figure this out. Two charges are separated by a distance of 0.5 m. Charge Q1 = -9 µC. The electric field at the origin is zero. a.What is the magnitude and sign of charge Q2? b.What is the magnitude and direction of the electric force between the charges? c.What is the electric energy of the system of two charges? d.What is the net electric potential at the origin? e.How much work is required to bring a negative charge of -1 nc from infinity to the origin? I have to make some assumptions because I do not have the picture that goes with this problem. Assuming that the charges are equal distance from the origin ie .25m.... k=1/(4*E0*pie)=9*10^9 a) Electric field add up. So the elctric field caused by Q1 at the origin is E=k(-9uC)/.25^2=-1294819.876V/M. Well Since we know that the E field is 0 and that the fields add up, we can use the formula 1294819.876V/M=kQ2/.25^2. We have to use a positive value because those 2 values added up will make the E field zero. So surprise surprise, the charge is equal but opposite. +9uC. Which should make sense. b) F=KQ1Q2/R^2=k*9uC*9uC/.25^2=11.65N Be sure when you actually write this out to put in units and show cancellations. c) I think they mean potential energy? Im not sure on this one. But its U=kQ1Q2/r = .324 N/m d) Net electric potential was figured in problem a. Its 0 since the electric field is 0. e) I don't feel like doing any integration A is incorrect, I have the answer key posted above. |