A point charge is at the origin With this point charge as th

A point charge is at the origin. With this point charge as the source point, what is the unit vector r^ in the direction of (a) the field point at x = 0 , y = -1.35m; (b) the field point at x= 12.0cm, y = 12.0cm; (c) the field point at x = - 1.10m, y = 2.60m? Express your results in terms of the unit vectors i^ and j^.

Solution

direction of eletric field from point charge is always sway from it. ( charge is +ve if negative then multiply unit vector with -1)

a) vector in direction = (0i - 1.35j) - (0i + 0j) = -1.35j

unit vector = vector / magnitude = 0i - 1j

b) vector in the direction = 12i + 12j

unit vector = (12i + 12j) / sqrt(12^2 + 12^2) = (12i + 12j) / 16.97

= 0.707i + 0.707j

c) vector in the direction = -1.1i + 2.60j

unit vector = (-1.1i + 2.60j ) / sqrt(1.1^2 + 2.6^2) = (-1.1i + 2.60j ) / 2.82

= -0.39i + 0.92j