A point charge `q = - 8.0 nC` is located at the origin. Find the electric field vector at the point `x = 1.2 m, y = -1.6 m`.

Options

A. `-14.4hat i+10.8hat j`
B. `-14.4hat i-10.8hat j`
C. `-10.8hat i+14.4hat j`
D. `-10.8hat i-14.4hat j`

Answer

C

Explanation

`vec(E ) = (1)/(4 pi epsilon_(0)) (q)/(r^(2)) hat r`
`hat (r ) =(vec(r ))/(r )=((1.2-0)hat(i)+(-1.6-0)hat j)/(sqrt((1.2)^(2)+(1.6)^(2)))`
`=(1)/(2)(1.2 hat(i)-1.6 hat(j))`
`vec(E )=9xx10^(9)xx((-8xx10^(-9)))/(2^(2))xx(1)/(2)(1.2 hat(i)-1.6 hat(j))`
`=-10.8 hat(i)+14.4hatj`.