Two point charges are fixed in vacuum: at the origin and on the -axis at

PHYSICS · Subjective · A Level · Physics · Fields and their consequences · Fields and their consequences

Problem

Two point charges are fixed in vacuum:

Q_1=+4.0\,\mu\text{C}

at the origin

(0,0)

and

Q_2=-3.0\,\mu\text{C}

on the

y

-axis at

(0,0.30\,\text{m})

. Consider the point

P

with coordinates

(0.40\,\text{m},0)

. (i) Calculate the electric field vector

\mathbf E_1

P

due to

Q_1

. (ii) Calculate the electric field vector

\mathbf E_2

P

due to

Q_2

. (iii) Determine the net electric field

\mathbf E_{\text{net}}

P

, giving its magnitude and direction with respect to the positive

x

-axis. (iv) A test charge

q=+2.0\times10^{-6}\,\text{C}

is now placed at

P

. Find the magnitude and direction of the force acting on it.