Question

A negative charge q₁ = -8.00 x 10^-6 C is at the origin. A positive point charge q₂ = 5.00 x 10^-6 C is on the x axis at x = 0.4 m. Point P is on the -y axis at y = -0.3 m. What are the x and y components of the net electric field at point P due to q₁ and q₂ ? Be sure to idicate whether each component is positive or negative.

Answer 1

from the given data

at point P,

E1 = k*q1/r1^2

= 9*10^9*8*10^-6/0.3^2

= 8*10^5 N/c (towards +Y axis)

E2 = k*q2/r1^2

= 9*10^9*8*10^-6/(0.4^2 + 0.3^2)

= 2.88*10^5 N/c

angle made by E2 with -x axis, theta = tan^-1(0.3/0.4)

= 36.9 degrees

so,

Ex = E1x + E2x

= 0 - 2.88*10^5*cos(36.9)

= -2.30*10^5 N/c <<<<<<<<---------------Answer

Ey = E1y + E2y

= 8*10^5 - 2.88*10^5*sin(36.9)

= 6.27*10^5 N/c <<<<<<<<---------------Answer