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Unformatted text preview: HW #3 From the textbook: P 427 P 432 A. For the power lines in problem 4.38, what is the capacitance between the lines per kilometer of transmission line? B. For the power line in problem 439, what is the capacitance per kilometer between the line and the ground? What is the impedance between the line and ground for a 10 km line? C. In prob. 421, you calculated the electric field from the electron distribution in a hydrogen atom. Suppose a 1000 V/m uniform electric field is applied to the atom. (a) By how much will the nucleus be displaced from the center of the electron cloud? (b) What is the resulting dipole moment of the atom? (c) Based on that, what is the electric susceptibility of hydrogen at standard temperature and pressure? (d) Based on that, what is the relative permittivity of hydrogen? (Hint, you can use the "ideal gas law" to figure the density of hydrogen. The measured value of susceptibility is e=2.475) D. A unit for electric dipole moment used in chemistry is the Debye (D). To convert to SI units, use the conversion: 1 D = 3.33564 x1030 Cm. Note that a Cm is ridiculously large for use in atomic scales. What is the force between two 1 C spherical charges 1 m apart? Express your answer in proper SI units and also in "imperial units", i.e. pound force. What is the dipole moment of a proton and an electron one angstrom (1010 m) apart? E. The dipole moment of the organic molecule 4pentyl4'cyanobiphenyl, a commonly used liquid crystal is 4.7 D. In a liquid crystal display, electric fields are used to line up the liquid crystal molecules changing the way they polarize light (see illustration below). If the distance between the electrodes is 0.2 mm, (a) what is the electric field intensity between the electrodes when 9V is applied as shown? (b) What is the torque on the LCD molecule that is not yet lined up with the field? In which direction is the torque vector? No voltage applied: Molecules orient randomly +9V ...
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- Spring '10