Two particles of -10 nC each are arranged symmetrically on the x-axis. 15 cm 91 = -10 nC 10 cm y •P 92 = -10 nC x 10 cm 2 (a) What is the electrostatic force (magnitude and orientation) on each of the two particles? (b) What is the net electric field in point P (magnitude and orientation)? (c) What is the net electric potential in point P?

Liquid water has a large dielectric constant of ɛ, = 80. Suppose that a single sodium ion (Na+, carrying a positive charge of +1e) is held in the middle of a beaker of pure water. Compared to the volume of the sodium ion, the volume of the water can be effectively treated as infinite. a) Write down the electric displacement at r distance away from the sodium ion. b) Write down the electric field at r distance away from the sodium ion. c) Write down the electrostatic force that the sodium ion acts on a water molecule that is 2nm away from the ion and oriented with its dipole moment radially away from the ion. d) Calculate the polarization at a distance r = 2nm away from the sodium ion. e) The dipole moment of a water molecule is 6.17 x 10-30C · m. Estimate how much fraction of the water molecules that are at 2nm away from the sodium ion are reoriented by the sodium ion. (Assume that there are only two possible states for these water molecules: either randomly oriented and showing zero…

A ▬ >E h d - As shown in the figure above, a positively charged ball is placed at point A and slides down the slope from rest. The area has a uniform electric field E = 12.9 N/C, pointing to the right. The mass of the ball is m = 9 kg and the charge is q = +2.6 C. When the ball reaches point B, it travels horizontally there after. The height from A to B is h = 37 m and the horizontal distance between A and B is d = 30 m. You can ignore friction and use g = 10 m/s for your calculation. %3D How much is the kinetic energy of the ball when it reaches at B (in the unit of J)? Submit Answer Tries 0/2 If the electric field ist changed to the opposite direction, How much is the kinetic energy of the ball when it reaches at B (in the unit of J) now? Submit Answer Tries 0/2 What is the minimum strength of electric field E that can be used to stop the particle right at Point B? N/C

Two parallel plates, each charged equally and oppositely to the other, are separated by 2.3500 cm. A proton is let go from rest at the positive plate's surface and, at the same time, an electron is let go from rest at the negative plate's surface. What is the distance between the negative plate and the point where the proton and the electron go by each other? Note: unlike most questions, this one will need your answer correct to 5 significant digits