In 1909, Robert Millikan and Harvey Fletcher designed an experiment to measure the electric charge of oil droplets by dropping them through an electric field, increasing the electric field strength until the droplets were suspended in the air. By repeating the experiment for many droplets, they confirmed that the charges were all small integer multiples of a certain base value, and thus they measured the charge of a single electron. In Millikan's experiment in the figure below, an oil droplet of mass 4.15 fg has an excess charge of five electrons. An electric field has been applied, and the droplet is levitating.  What is the magnitude of the electric field? (Units: N/C)

The figure below shows the electric field lines for two point charges separated by a small distance. (a) What are the signs of q1 and q2? (b) Determine the ratio q1/q2. Express your answer to 3 significant figures.

A simple electroscope to measure electrical charges is made up of two cork spheres covered with metal sheets, each sphere weighs 1.25x10-4 kg and hangs from a 12 cm long thread, when equal electrical charges are added to the spheres, the force of electrical repulsion moves them away and the angle between the wires indicates the magnitude of the electric charge, if the equilibrium angle between the wires is 500, what is the magnitude of the electric charge?

How many charges will it take to make up a µC?

You are given a container with 100 g of hydrogen atoms. What is the total charge on the electrons in the container ?

A typical AA size rechargeable NiMH battery can store 1100-2100 mAh of electric charge. The small print on the battery in your hand says 1530 mAh. Can you express this amount of electric charge using the usual coulomb units? You are now charging a camera battery. The charger moves 4470 C of electric charge from the negative terminal of the battery to the positive terminal. (In reality the charger moves the negative electrons from the positive terminal to the negative terminal, but this is not important for us right now.) Assuming - incorrectly - that the voltage of the battery remains a constant 3.20 V during the whole charging process, determine the work done by the charger. And now you are charging a capacitor bank for a high-voltage physics experiment. The power supply moves Q = 8990 C of electric charge in the charging process. The supply is set to stop, when the voltage reaches AV = 710 V. How much work did the power supply perform?

Two identical brass balls mounted on wooden posts initially have different amounts of charge, one at +6 uC and the other at -20 uC. The balls are allowed to touch and then are separated again. What is the final charge on each ball? Group of answer choices -7 uc -14 uC 7 uC 13 uc

Electrostatic force (in Newtons)between two charges is given by the formula, Fe=kq1 q2/r^2, where k is about 9E9. The amount of charge in a AA battery is about 9000 coulomb. Suppose you took two AA batteries and dumped one of the battery's charge in the purple pile and the other battery's charge in the red pile. You place the piles 9 meters apart. What is the electrostatic force between the two charges? (You should be able to do this math in your head) Select: (1E6 N, 7.29E17 N, 8.1E16 N, or 9E15 N) Is this a repulsive or attractive force? Select: (neither, repulsive, or attractive)To increase the magnitude of this force, would you increase or decrease the distance between them? Select: (increase, decrease, or depends on direction)

A system of 1358 particles, each of which is either an electron or a proton, has a net charge of -1.002x10-16 C. How many electrons are in this system (exactly)? Submit Answer Tries 0/32 What is the mass of this system (to three significant digits)?

A system of 1455 particles, each of which is either an electron or a proton, has a net charge of −6.704×10−17 CC . What is the mass of this system?