Exam 1 practice problems

Exam 1 practice problems - Exam 1 practice problems Physics...

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Exam 1 practice problems Physics 204 1. Nuclear fusion is a highly sought after alternate energy source because it is environmentally friendly and uses very abundant fuels. However, it is a technical challenge to get two atomic nuclei to fuse. One way to get two nuclei to fuse is to strip off their electrons then accelerate the nuclei to high speed and collide them together. Using this idea it is possible to fuse two deuterium nuclei into helium. Deuterium is an isotope of hydrogen, having one proton and one neutron in its nucleus. a. If the two deuterium nuclei need to get within 15 1.3 10 m of each other for them to fuse into helium, predict what speed they must be fired at to get that close. b. Describe any assumptions you made in making your prediction. 2. A carbon dioxide (CO 2 ) molecule consists of two oxygen atoms and one carbon atom in the arrangement shown. Oxygen atoms are more electronegative than carbon atoms, which effectively makes the ends of the molecule slightly negatively charged ( 20 2.00 10 C  ) and the center of the molecule slightly positively charged ( 20 4.00 10 C  ). a. Using the details of this model of the CO 2 molecule, make a conceptual argument for what direction the electric field points at location A. b. Predict the mathematical value of the electric field at the point indicated. 3. An electric dipole is a pair of pointlike charges of equal magnitude but opposite in sign separated by a fixed distance. You decide to build one by taking two small copper spheres and gluing them to the ends of a plastic tube. Predict the value of the electric field at a point on the perpendicular bisector between the two spheres as shown in the diagram. 4. Three glass spheres of positive charge 9 10 QC are arranged so that they are located at the corners of a square of side 0.1 Lm . A proton is placed at the center of the square, then released so it may move freely. a. Sketch a picture of the situation and describe in words the resulting motion of the proton. Be as specific as you can with your description. b. Predict the speed of the proton once it once it reaches the empty corner. (Hint: Remember to use the principle of superposition.) O O C 10 1.16 10 m A 11 5.00 10 m 7 4.00 10 qC  7 4.00 10   5.00 L cm 10.0 d cm This point

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5. A parallel plate capacitor might also be used to determine the speed of charged particles. Imagine that a beam of electrons is being fired into the parallel plate capacitor as shown. The power source has the ability to be adjusted so that the potential difference that it provides is just enough so that the electrons do not reach the negative plate. If this happens when the power source is set to 10.3 V then how fast are the electrons traveling when they enter the capacitor?

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This note was uploaded on 01/31/2011 for the course PHYS 204 taught by Professor Brahmia during the Spring '10 term at Rutgers.

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Exam 1 practice problems - Exam 1 practice problems Physics...

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