A red blood cell contains 4.1 x 10^10 free electrons. What is the total charge of these electrons in the red blood cell? C
A particle of charge 2.3 x 10^-8 C experiences an upward force of magnitude 4.2 x 10^-6 N when it is placed at a particular point in an electric field. (Indicate the direction with the signs of your answers. Assume that the positive direction is upward.)
a) What is the electric field in N/C at that point? N/C
b) If a charge q = -1.9 x 10^-6 C is placed there, what is the force in N on it? N