- #1

- 219

- 0

http://img367.imageshack.us/img367/5459/69671206ju9.th.jpg [Broken]

See image above. Point charges A, of +2.0nC, and B, of –3.0 nC, are 200mm apart in a vacuum, as shown by the figure. The point P is 120mm from A and 160mm from B.

(i) Calculate the component of the electric field at P in the direction AP.

(ii) Calculate the component of the electric field at P in the direction PB.

The markscheme uses E= kQ/(r^2)

where k = 1/4*pi*epsilon

However, for part (i), uses only the 2nC charge, while uses only the -3nC charge for part ii - can someone please explain why this is the case.

Thanks

See image above. Point charges A, of +2.0nC, and B, of –3.0 nC, are 200mm apart in a vacuum, as shown by the figure. The point P is 120mm from A and 160mm from B.

(i) Calculate the component of the electric field at P in the direction AP.

(ii) Calculate the component of the electric field at P in the direction PB.

The markscheme uses E= kQ/(r^2)

where k = 1/4*pi*epsilon

However, for part (i), uses only the 2nC charge, while uses only the -3nC charge for part ii - can someone please explain why this is the case.

Thanks

Last edited by a moderator: