1. Consider two charges as shown in figure below: P r = 2m r = 2m 60 60 +q -q Which of the following is correct for the net electric field Enet and total electric potential Vtotal at point P? A. Enet = 0, Vtotal = 0 B. Enet = 4 ' Ka , Vtotal = 0 C. Enet = 4 Ka, Vtotal = 0 D. Enet = 0, Vtotal = Ka 4 . E. Enet = 0, Vtotal = Kq2 4 2. The interplanar spacing of a typical set of NaCl crystal planes is d = 0.282 nm. A monochromatic beam of x-rays produces a second-order Bragg maximum when its glancing angle with these planes is 0 = 10.23. Which of the following is correct for the wavelength (1) of the x-rays and the minimum possible accelerating voltage (Vo) that produced the x-rays? A. 1 = 100 pm, Vo = 12.4 kV B. A = 100 pm, Vo = 24.8 kV C. 1 = 50 pm, Vo = 12.4 kV D. A = 50 pm, Vo = 24.8 kV E. None of the ones given here 3 . An organ pipe (L = 2.0 m) is closed at both ends. Compute the frequencies of the first three modes of resonance. Assume the speed of sound is 340 m/s. A. f1 = 170 Hz, f2 = 340 Hz, f3 = 510 Hz B. fi = 510 Hz, f2 = 340 Hz, f3 = 170 Hz C. f1 = 85 Hz, f2 = 255 Hz, f3 = 425 Hz D. f1 = 255 Hz, f2 = 170 Hz, f3 = 85 Hz E. f1 = 85 Hz, f2 = 170 Hz, f3 = 255 Hz4. A diffraction grating with 10,000 lines per centimeter is irradiated with a beam of white light through it to a screen 2.00 m away. OR =? Ov =? YR - VV =? YR = ? Grating OR = ? yv - ? x = 2.00 m- Screen In figure shown, Ov and OR are the angles for the first-order diffraction of the shortest and longest wavelengths of visible light (380 and 760 nm) respectively. If Ay(VR - Vv) is the distance between the ends of the rainbow of visible light produced on the screen for first- order interference, which of the following is correct for Ov, OR and Ay(VR - Vv)? A. Ov = 49.46, OR = 22.33, Ay(VR - Vv) = 1.52 m B. OR = 49.46, Ov = 22.33, Ay(VR - Vv) = 1.52 m C. Ov = 49.46, OR = 22.33, Ay(VR - Vv) = 27.13 m D. OR = 49.46, Ov = 22.33, Ay(VR - Vv) = 27.13 m E. OR = 49.46, Ov = 22.33, Ay(VR - Vv) = 0.52 m5. Each of the double bonds in retinal, shown in figure below, has two valence electrons that are free to roam around the molecule. These are the electrons that you can model as standing waves within the total length L of the retinal. Visible Spectrum 700 mm 400 m - - LU OOS 600 m - H3C CH3 CH3 CH3 O Orange Violet Yellow Green Indigo H Single-bond length = 0.154 nm CH3 Double-bond length = 0.134 nm Red orange Yellow Green Blue Indiga Violet Since there are two valence electrons per energy level, one of the possible transitions can be possible from the lowest un-occupied energy level to the second highest occupied energy level. If such a transition is caused by the light from a typical GaAsP-based light-emitting-diode (LED), which of the following correctly characterizes the LED in terms of what wavelength radiation is emitted? A. 1 = 322 nm, ultraviolet (UV) B. 1= 380 nm, violet C. 1 = 475 nm, blue D. 1 = 525 nm, green E. 1 = 594 nm, yellow F. 1 = 690 nm, redWhat is the electric potential energy (EPE) of the system in assembling four charges as shown? \"1 4.0cm A. K02 2 B. \"7': C, % D. \"'32 E. Zero 7. A right isosceles triangle of side a has charges +q, +2q and -q arranged on its vertices, as shown in figure below: + P a + 29 a -q Which of the following is correct for the electric potential Up at point P, midway between the line connecting the +q and -q charges, assuming that the electric potential is zero at infinity and that the electrostatic constant is K? A. Vp = 2V2Kq a B. Vp = V2Kq a C. Vp = 2Kq Zoom Out a D. Vp = 4 Kq a E. ZeroIn the tape experiment, it is possible to oat one U-tape above another U-tape, as shown in the diagram below. B . . p coma ' ' - . chugeq . obpu' may\": dotted line shows original position 0! tape B Consider tape B to be the system of interest and tape A to be in the surroundings. Under the assumptions that both pieces of tape have the same net charge q and that the excess charge of each tape is located at a single point in the center of the tape, the total charge on tape B that has a length l with an average linear mass density um\" is A. q = \"raj:le B. q = d \"mfg C. q _ Fraiegd D. q = #mpgeKd E. q _ I-ltapeHK 9. A dipole is held motionless in a uniform electric field, as shown in figure below: + When the dipole is released, which of the following describes the subsequent motion? A. The dipole moves to the right. B. The dipole moves to the left. C. The dipole rotates clockwise. D. The dipole rotates counterclockwise. E. The dipole remains motionless.10. The graphs at the right in figure below show the electric potential of a uniformly charged membrane in an ionic solution as a function of distance away from the membrane. Both curves represent the same concentration of ions, but they are at different temperatures. Concentration n- Coulomb's Law KBTK AD = Ve= kelr VATkcCoq? n+ Potential [arbitrary units] N Shielded Potential ap Distance co : average bulk concentration 9 : object charge Vs = kQeb Ir T: temperature k : dielectric constant ke : electric constant (9x109 Nm/C?) KB : Boltzmann constant (1.38x10-23 J/K) Which of the following is correct? A. Vc = Vse-r/D; and Ap increases as temperature increases. B. Vc = Vse-r/AD; and Ap decreases as temperature increases. C. Vs = Veer/AD; and Ap increases as temperature increases. D. Vs = Veer/AD; and Ap decreases as temperature increases. E. Vs = Vcetr/AD; and Ap increases as temperature increases. 11 . A parallel-plate capacitor has square plates 7.5 cm on a side, separated by 0.29 mm. The capacitor is charged to 12 V, then disconnected from the charging power supply. Which of the following is correct for the capacitance C (expressed in nano-farads, nF) of this capacitor and the energy density up (expressed in milli-joules per cubic-meter, m.J/m') in the electric field between the plates? A. C=1.7 nF, Up = 0.765 mJ/m' B. C= 0.765 nF, UE = 1.7 m.J/m' C. C = 17 nF, UF = 765 mJ/m' D. C =7.65 nF, UE = 0.17 m.J/m' E. C=0.17 nF, Up = 7.65 m.J/m312. A 600-W toaster operates at 120 V supply. Which of the following is correct for the resistance R of its heating element and the total charge 11 passing through it in an hour? R:5 ,q:8.64 X104C 12:24 n,q: 1.80 x104 c R25 (2,11: 1.80 x104c R:24 0., q : 8.64 X104 C R : 0.2 0., q : 1.80 x104 C W909\"? 13. A positively charged particle q1 = +10 nC is held stationary at a fixed position. A second charge q2 of mass m = 3.5 ug is located a distance d = 15 cm directly above charge q1. The net force on q2 is equal to zero. You may assume that this system is close to the surface of the Earth. 92 d 91 Which of the following is correct for the charge q2? A. The charge q2 must be negative with its magnitude q2 = 8.6 pC. B. The charge q2 must be positive with its magnitude 92 = 8.6 pC. C. The charge q2 must be negative with its magnitude q2 = 10 nC. D. The charge q2 must be positive with its magnitude q2 = 10 nC. E. The charge q2 must be positive with its magnitude q2 = 5 nC