A 3.0-mm-diameter copper ball is charged to 90  nC. What fraction of its electrons have been removed? The density of copper is 8900  kg/m3.

Answer the following

How many electrons must be removed from a neutral object to leave a net charge of Q2 = 2.1 μC?

Four identical metallic objects carry the following charges: +1.23, +6.89, -4.44, and -9.28 μC. The objects are brought simultaneously into contact, so that each touches the others. Then they are separated. (a) What is the final charge on each object? (b) How many electrons (or protons) make up the final charge on each object? (a) Number i (b) Number IN Units Units

Two metal spheres, each of radius 3.1 cm, have a center-to-center separation of 1.5 m. Sphere 1 has a charge of +1.3 × 10-8 C; sphere 2 has a charge of -2.7 x 10-8 C. Assume that the separation is large enough for us to assume that the charge on each sphere is uniformly distributed (the spheres do not affect each other). With V= 0 at infinity, calculate in volts (a) the potential at the point halfway between their centers and the potential on the surface of (b) sphere 1 and (c) sphere 2.

Two metal spheres, each of radius 3.4 cm, have a center-to-center separation of 2.5 m. Sphere 1 has a charge of +1.2 × 10-8 C; sphere 2 has a charge of -3.2 × 10-8 C. Assume that the separation is large enough for us to assume that the charge on each sphere is uniformly distributed (the spheres do not affect each other). With V = 0 at infinity, calculate in volts (a) the potential at the point halfway between their centers and the potential on the surface of (b) sphere 1 and (c) sphere 2.

(a) Calculate the number of electrons in a small, electrically neutral silver pin that has a mass of 8.0 g. Silver has 47 electrons per atom, and its molar mass is 107.87 g/mol. (b) Imagine adding electrons to the pin until the negative charge has the very large value 3.00 mC. How many electrons are added for every 109 electrons already present?

Two 1.7-cm-diameter disks face each other, 1.5 mm apart. They are charged to ± 10 nC. What is the electric field strength between the disks? A proton is shot from the negative disk toward the positive disk. What launch speed must the proton have to just barely reach the positive disk?

(a) Calculate the number of electrons in a small, electrically neutral silver pin that has a mass of 13.0 g. Silver has 47 electrons per atom, and its molar mass is 107.87 g/mol. (b) Imagine adding electrons to the pin until the negative charge has the very large value 1.00 mC. How many electrons are added for every 109 electrons already present?

Consider the following. B 0.500 mm 60.0° (a) Red blood cells often become charged and can be treated as point charges. Healthy red blood cells are negatively charged, but unhealthy cells (due to the presence a bacteria, for example) can become positively charged. In the figure, three red blood cells are oriented such that they are located on the corners of an equilateral triangle. The red blood cell charges are A = 1.80 pC, B = 6.60 pC, and C = -4.40 pC. Given these charges, what would the magnitude and direction of the electric field be at cell A? magnitude N/C direction ° counterclockwise from the +x axis (b) If the charge of cell A were doubled, how would the electric field at cell A change? O The magnitude of the field would be doubled. O The field would be unchanged. O The magnitude of the field would be halved. O The magnitude of the field would be quadrupled.