4. Two charges, q₁ -2.00 X 10^-6 C and q₂ = -1.80 X 10^-5 C, are separated by a distance, L, of 4.00 m. A third charge, q₃ = 1.50 X 10^-6 C, is placed somewhere between q₁ and q₂, where the net force exerted on q₃ by the other two charges is zero. Determine the location of q₃.

5. An electron moves horizontally with a speed of 1.55 X 10⁶ m/s between two horizontal parallel plates(positive plate is on top). The plates have a length of 11.9 cm, and a plate separation that allows a charged particle to escape even after being deflected. The magnitude of the electric field within the plates is 155 N/C. Calculate the final velocity of an electron as it leaves the plates.