# PHY2054:Exam 2 - University of Florida PHY2054:Exam 2 Tuesday 11/8, 8:20-10:10PM You must bring pencils and erasors, a calculator and your UF ID You are allowed a one page formula sheet. No hats please. No electronic communication things, Wi-Fi, cell phones or computers. A-C WM 100 D-G Weil 270 H-L LIT 101 M-P

LIT 109 Q-T MccAG186 U-Z LIT 113 Review Exam 2 Coverage: Ch. 18-23.5 Skip 18.8, 19.10, 21.1-7 and 21.9-10 18: DC circuits, Kirchhoffs rules 19: Magnetism 20: Faradays law 21: Electromagnetic waves 22: Reflection and refraction of light 23: Mirrors.

PHY2054:exam 2 Look at problems from old exams. Exam 2 in most cases but for Chapter 23, consider final. Work in a group. Some solutions are available. Make sure that you can do the problem. Remember that a trick on a bicycle, shown by some one else, means that : It can be done. The person who shoed it can do it. You might hurt yourself on the first try.

PHY2054: Exam 2 Chapter 18: Series : Req = R1+R2+R3 Parallel: 1/Req = 1/R1 +1/R2 + Kirchhoffs rules: Junctions, branches and loops Junctions- total current in = total current out Potential drop summed around a closed loop = 0 q = Q(1-exp (-t/RC))

PHY2054: exam 2 Calculate the equivalent resistance Show that the rsistance between points a and b is 12/27. (apply a apply a battery) PHY2054:Exam 2 The current in series is the same,

the voltages add up In parallel resistors, the potential drop is the same and the currents add. In RC circuits q(t) = Q[1 exp(-t/RC)] Fig. P18-47, p. 623 PHY2054:exam 2

Magnetism: F = qvxB r = mv/qB F = l IxB = NIAB sin what is ? Wire B = oI/2rrr Loop B = oI/2rr Solenoid B = noI Force between two wires F = l oI1I2r/2rrd Fig. 18-16, p. 607

PHY2054: exam 2 = BA cos = -/t Motional emf = Blv (bar moving in field and on rails) Force on bar (Bl)2v/R = NBAw sin wt = L dI/dt I = V/R[1 exp(-t/RC)] Fig. 18-17, p. 607 PHY2054: exam 2

Chap. 21. Electromagnetic waves. Speed 1 ft/ns. 3x108 m/s B = E/c c = f P = U/c total absorption I = E2/2oc Watt/m2r Force = IA/c Dopplers effect

fo = fs (1 u/c) Fig. P18-58, p. 624 PHY2054: Exam 2 Reflection and Refraction n sin = constant sin c = n2r/n1 PHY2054: Exam 2

Images 1/p + 1/q = 1/f f = R/2 m = - q/p Mirror concave f >0 Image real q>0 straight, m >0 amplified |m | >1 PHY2054: Exam 2

GOOD LUCK