# electrically-charged spheres electrostatic force, Physics Homework Help

Science

• Two electrically-charges spheres are suspended from insulated threads a certain distance from each other.  There is a certain amount of electrostatic force between them.  Describe specifically (not just increase or decrease) what happens to this force in each of the scenarios below (1 pt. ea.):
• The charge on one sphere is reduced by half
• The charge on both spheres is doubled
• The distance between the spheres is increased by a factor of three
• The distance between the sphere is decreased to one-fourth
• The charge of each sphere is doubled and the distance between them is doubled
• An ammeter indicates the current for a toaster is 5.0 amps when the toaster is connected to 120-V circuit.  How much energy is given off by the toaster in 55.0 seconds?  Show all calculations leading to an answer.
• Three identical light bulbs are connected in series, then are disconnected and arranged in parallel.  For each of the scenarios below indicate what changes (if any) take place (1 pt. ea.):
• Total resistance of the circuit
• Total current of the circuit
• Power dissipated by the circuit
• Voltage used by one of the light bulbs
• Resistance of one of the light bulbs
• Using 3 – 4 sentences, explain, in your own words, two ways you could cause an electrical current using only a wire and a horseshoe magnet.
• Using 3 – 4 complete sentences, explain the role of both types of transformers in getting electric energy from an electric power plant (coal-fired, natural gas or nuclear) to our homes.
• In what way does the photoelectric effect support the particle theory of light?  Use 3 – 4 complete sentences in your own words to explain.
• The isotope, Carbon-14 emits beta radiation and has a half live of 5730 years.  How long will it take for the amount of radiation this gives off to drop by a factor of 4?
• The total U.S. consumption of electricity in a particular year was 5.0 x 1012 kilowatt-hours.  What is the mass equivalence of this amount of energy?  Show all calculations leading to an answer.
• When uranium-238 emits an alpha particle, what isotope is created?  Show the nuclear equation for this reaction.