Electrons have a charge of q = -1.602 × 10-19 C. A student observes that a Styrofoam cup has a total charge of Q = -0.98 μC. Write an expression for the number of excess electrons N in the cup.

You hold a ruler that has a charge on its tip 4.00 cm above a small piece of tissue paper to see if it can be picked up. The ruler has  −10.0 µC  of charge. The tissue has 1.00 g of mass. What is the minimum charge required to pick up the tissue paper?

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

Two pith balls, each of mass m = 0.2 × 10−3 kg are suspended from the same point by silk threads each 0.4 m long. An equal charge q is given to each of the pith balls, which causes them to separate by a distance d until the threads are at an angle of 40 degrees to each other. Calculate the magnitude of the charge on each ball.

Blocks A and B are identical metal blocks. Initially block A is neutral, and block B has a net charge of 7.4 nC. Using insulating handles, the blocks are moved so they touch each other. After touching for a few seconds, the blocks are separated (again using insulating handles). (a) What is the final charge of block A?

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.

A metal sphere has a charge of -7.86 nC and an additional 2.43 x 109 electrons are added. What is the final charge of the sphere? Please give your answer in nC, 1 nC = 10-9 C.

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 metal wire is bent to the shape of a circular arc as shown in the figure. The arc is centered around the origin. Please, notice that the arc goes through grid intersection points. 8 7654 3 y (cm) do 4d in to w N 117 -6 -8 -8-7-6-5-4-3-2-1 0 1 2 3 4 5 6 7 8 x (cm) The wire has a constant linear charge density of 1.81 nC/cm. What is the total electric charge of the wire? Submit Answer Incorrect. Tries 1/20 Previous Tries What is the x-component of the electric field at the origin due to the charged wire? Submit Answer Incorrect. Tries 1/20 Previous Tries What is the y-component Submit Answer Tries 0/20 the electric field at the origin?

Common static electricity involves charges ranging from nanocoulombs to microcoulombs. (a) How many electrons are needed to form a charge of −4.50 nC? (b) How many electrons must be removed from a neutral object to leave a net charge of 0.410 µC?