Suppose a speck of dust in an electrostatic precipitator has Np = 3.75 × 1017 protons in it and carries a net charge of Q = -76 nC. Let qe represent the charge of an electron. a) Enter an expression for the number of electrons Ne in the speck of dust in terms of the charge of an electron, qe, and other variables from the problem statement. b)  How many electrons are in the speck of dust?

Point charges of +2 µC and -8 µC are at points A and B respectively. Find the magnitude and direction of the electric field strength at point P which is 10 cm from both A and B.

The two spherical shell has a charge of q1=0.30nC and q2 = 0.5nC. The radius of r1=7.5cm and r2 = 2.5cm. What is the new votage value in volts, after the charge transfer is completed between the two spheres?

A small drop of water is suspended motionless in air by a uniform electric field that is directed upward and has a magnitude of 10000 N/C. The mass of the water drop is 5 x 10-9 kg (b) How many excess electrons or protons reside on the drop? Give your answer in scientific notation correct to one decimal place.

A red blood cell typically carries an excess charge of about −2.5×   10-12 C distributed uniformly over its surface. The cells, modeled as spheres, are approximately 7.5 μm in diameter and have a mass of 9.0×   10-14 kg.   (a) How many excess electrons does a typical red blood cell carry? (b) What is the surface charge density σ on the red blood cell? Express your answer in C/m2 and in electrons/m2. σ = C/m2 = electrons/m2

Two conducting spheres, A and B, have the same radius and sit on insulating stands. When they are touched together, 3.05×1013 electrons flow from sphere A to sphere B. If the total net charge on the spheres is +2.10 μC, what was the initial charge on sphere B?

Four identical metallic spheres with charges of +1.4 μC, +1.8 μC, -5.8 μC, and -5.2 μC are placed on a piece of paper. The paper is lifted on all corners so that the spheres come into contact with each other simultaneously. The paper is then flattened so that the metallic spheres become separated. (a) What is the resulting charge on each sphere? μC (b) How many excess or absent electrons (depending on the sign of your answer to part (a)) correspond to the resulting charge on each sphere? electrons are ---Select---

Four identical metallic spheres with charges of +9.0 µC, +2.6 µC, -3.4 µC, and -7.2 µC are placed on a piece of paper. The paper is lifted on all corners so that the spheres come into contact with each other simultaneously. The paper is then flattened so that the metallic spheres become separated. (a) What is the resulting charge on each sphere? µC (b) How many excess or absent electrons (depending on the sign of your answer to part (a)) correspond to the resulting charge on each sphere? electrons are ---Select--- Additional Materials Reading

The earth has an excess of 6.0 x 10^5 electrons on each square centimeter of surface. Calculate the electric charge in Coulombs on each square centimetre of surface. (b) As you walk across a rag 9.0 x 10^33 kg of electrons transfer to your body. Calculate the number of electrons and the total charge in coulombs on your body.