Chapter $22$: Particle $1$ has charge $+1\mathrm{.}3{10}^{-5}C$ and is positioned at the origin. Particle $2$ has charge $-2\mathrm{.}4{10}^{-5}C$ with a location of $(+1\mathrm{.}0m,0m).$ Particle $3$ has charge $-1\mathrm{.}6{10}^{-5}C$ with a location of $(0m,+2\mathrm{.}0m).$ What are the magnitude and direction of the vector sum of the forces acting on particle $1?$

Chapter $23$: The electric force due to a uniform external electric field causes a torque of magnitude $1\mathrm{.}0{10}^{-9}N*m$ on an electric dipole oriented at $30$ from the direction of the external field. The dipole moment of the dipole is $8\mathrm{.}0{10}^{-12}C*m.$

a$.$ What is the magnitude of the external electric field?

b$.$ If the two particles that make up the dipole are $2\mathrm{.}5mm$ apart, what is the magnitude of the charge on each particle?