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 2Coverage: Ch. 18-23.5Skip 18.8, 19.10, 21.1-7 and 21.9-1018: DC circuits, Kirchhoff’s rules19: Magnetism20: Faraday’s law21: Electromagnetic waves22: Reflection and refraction of light23: 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 + …

• Kirchhoff’s rules:Junctions, branches and loops– Junctions- total current in =

total current out– Potential drop summed

around a closed loop = 0q = Q(1-exp (-t/RC))

PHY2054: exam 2

• Calculate the equivalent resistance

• Show that the résistance between points a and b is 12/27Ω. (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• τ = NIAB sin θ what is θ?

• Wire B = μoI/2πr

• Loop B = μoI/2r

• Solenoid B = nμoI

• Force between two wires F = l μoI1I2/2πd

Fig. 18-16, p. 607

PHY2054: exam 2• Φ = BA cos θ• 𝓮 = -Δφ/Δt• Motional emf 𝓮 = Blv (bar moving in field and on rails)• Force on bar (Bl)2v/R• 𝓮 = NBAw sin wt• 𝓮 = 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 = fλ• P = U/c total absorption• I = E2/2μoc Watt/m2 Force = IA/c

• Doppler’s effect– fo = fs (1 u/c)

Fig. P18-58, p. 624

PHY2054: Exam 2

• Reflection and Refraction

• n sinθ = constant• sin θc = n2/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 >0amplified |m | >1

PHY2054: Exam 2

• GOOD LUCK