Physics Final Exam revision c4/8/15
Directions:It is important that you provide answers in your own words. Please focus only on information from the text/eBook to create your own solutions. Please do not use direct information from an outside source (especially copying and pasting from an “answer” website). Use of direct information from an outside source is against school policy. All answers will be checked for plagiarism. Instances of plagiarismcan result in probation or possible dismissal from the school.
Grading: Please be sure to follow all guidelines (number of sentences/showing all calculations) and to provide the correct metric units of measure. It is important for you to observe the number of sentences, when required. This helps me assure the integrity of your responses. All questions are 5 points (1 point for sentence number /correct units).
Consider eight,eight-cubic centimeter (8 cm3) sugar cubes stacked so that they form a single 2 x 2 x 2 cube. How does the surface area of the single, large cube compare to the total surface area of the individual eight cubes? Report your answer as a ratio. Be sure to show all calculations leading to an answer.
A rectangular barge 7 m long and 2 m wide floats in fresh water. How much will the barge sink when loaded with 600 kg of sand? Show all calculations leading to an answer.
When a steadily-flowing gas flows from a larger-diameter pipe to a smaller-diameter pipe, what causes the pressure in the smaller pipe to drop? Use 3 – 4 complete sentences to explain your answer.
When a 3-kg iron skillet is heated on the stove, it becomes hot very quickly. When 3 kg of water is heated on the stove it heats up slowly. What is the reason for this difference? Support your answer using 3 – 4 complete sentences.
In a lab experiment, 45 grams of a metal are heated from 22⁰C to 78⁰C by the addition of 450 J of heat. What is the specific heat of the metal? Show all calculations leading to an answer.
A photon of light has a wavelength of about 600 nm (1nm = 1 x 10-9 m). What is the energy of this photon of light? Show all calculations leading to an answer.
When a wave crosses a surface at an angle from one medium into another, why does it change directions as it moves across the boundary into the new medium? Use 3 – 4 complete sentences in your own words to explain.
Suppose a piano tuner hears 2 beats/second when listening to the combined sound from the tuning fork and the piano note being tuned. After slightly loosening the string, she hears 1 beat/second. Should she continue to loosen the string or tighten it in order to get it “in tune”? Defend your answer with 3 – 4 complete sentences.
What conditions must exist for a converging lens to produce a real image of an object that is larger than the object itself? Please respond with 3 - 4 complete sentences.
Suppose the thickness of an oil film on water is just the right thickness for canceling red light. What color will your eye see? Explain using 3 – 4 complete sentences.
A hard-rubber or plastic comb rubbed against wool can often be shown to have a static charge. Why does a metal comb not readily show a static charge when rubbed against wool? Use 3 – 4 complete sentences in your answer.
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.