1. 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

2. Review Exam 2 Coverage: Ch. 18-23.5
Skip 18.8, 19.10, and
18: DC circuits, Kirchhoff’s rules
19: Magnetism
20: Faraday’s law
21: Electromagnetic waves
22: Reflection and refraction of light
23: Mirrors.

3. 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.

4. 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 = 0
q = Q(1-exp (-t/RC))

5. PHY2054: exam 2 Calculate the equivalent resistance
Show that the résistance between points a and b is 12/27Ω. (apply a battery)

6. 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

7. 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
Figure 18.16
(a) A capacitor in series with a resistor, a battery, and a switch. (b) A plot of the charge on the capacitor versus time after the switch on the circuit is closed. After one time constant τ, the charge is 63% of the maximum value, Cε. The charge approaches its maximum value as t approaches infinity.
Fig , p. 607

8. 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)]
Figure 18.17
(a) A charged capacitor connected to a resistor and a switch. (b) A graph of the charge on the capacitor versus time after the switch is closed.
Fig , p. 607

9. 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

10. PHY2054: Exam 2 Reflection and Refraction n sinθ = constant
sin θc = n2/n1

11. 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

12. PHY2054: Exam 2
GOOD LUCK