PHYS 222 SI Exam Review

1. PHYS 222 SI Exam Review

2. What to do to prepare • Review all clicker questions, but more importantly know WHY • Review quizzes • Make sure you know what all the equations do, and when to use them

3. These equations are used exclusively in LRC circuits • These equations are what let you find the major constants that do not change with time. • Remember, capital letters are not time dependent.

4. These equations are used to determine the root-mean square voltage and current in an LRC circuit

5. These two equations assume that the current in an LRC circuit is a maximum at t=0. • These equations tell the voltage and current as a function of time. • To find remember to add the appropriate phase constants to the cos term.

6. Not mentioned in class really

7. AC Current section on the Equation Sheet • All the capitalized letters do not change with time. • For example…none of these change with time: • V, I, • To find the time dependent voltage and current, multiply by the appropriate time dependent equation.

8. How to determine v(t), i(t), • The current phasor is parallel with the phasor. • leads , and lags • The voltage • I.E. if then

9. What happens to a circuit at resonant frequency? • The voltage phasor is parallel with the current phasor(this does not usually happen) • (recall that both do not depend on time) • The sum of the voltages across the inductor and the capacitor equals 0.

10. Example #1 • At t=0, the current in the circuit is a maximum of 3 A. • Then… • Also note that without doing any math you know that and • Make sure you understand why.

11. Example #2 • Let’s say that in an LRC circuit, • Also suppose that you’ve calculated the phase angle to be, and • Then

12. Example #3 • They tell you • To calculate I, find Z, then use • To calculate , first find I, then use • Finally, if you need time dependence, add the appropriate phase shift to the cos or sin.

14. Equation relating power, current, and voltage

15. Average power in an LRC AC circuit

16. Equations used to convert a voltage inside a transformer

17. Current and voltage in a transformer

18. The equations for electromagnetic radiation, or in other words light • Note that the direction of propagation is +x. • Also note that

19. Speed of light related to two constants

20. Energy density

21. Equations relating the radiation pressure of an electromagnetic wave to the poynting vector and E and B.

22. Poynting vector. • Note that the poynting vector is perpendicular to both E and B

23. The intensity of electromagnetic radiation, related to the E field.

24. Equations relating the speed of light c, the wavelength of light , the frequency of light the angular frequency , and the wave number .

25. The speed of light in a medium of index of refraction . • For example, in glass the speed of light is not equal to m/s, but instead it’s equal to m/s (

26. The equations for reflection and refraction

27. The equation for intensity of light through a diffraction grating.

28. The equation used to find the critical angle between two interfaces. • At angles equal to or greater than the critical angle, refracted rays stop going through the second medium. Instead they undergo total internal reflection. • Sometimes light coming from one direction onto an interface doesn’t have a critical angle, but if the light goes the other direction, then the critical angle exists.

29. Equation used to find Brewster’s Angle, also known as the Polarization Angle . • This angle is where reflection stops happening.

30. The master equation for both lenses AND mirrors

31. ALWAYS…s>0. (the distance from the real object to the vertex of the mirror, or from the real object to the lens) • For MIRRORS… • f>0 if the mirror is concave, if the mirror is convex, then f<0. Also f=R/2. • s’>0 if the image is on the same side as the outgoing rays • For LENSES… • f>0 if the lens is more converging, otherwise f<0 if the lens is more diverging

32. Magnification caused by a mirror or lens

33. Focal point of a spherical mirror

34. “Lensmaker’s Equation”

35. Look up

36. Spherical fish bowls is the main application of this equation

37. M is the angular magnification of a telescope. • Recall that and

38. This is the equation for two-source interference, used to find where the bright fringes are. • To find the dark fringes, replace m with (m+1/2)

39. Destructive interference.

40. Assuming small angles the equation on the previous slide gives this result, where R is the distance between the slits and the screen, d is the separation of the slits, m is an integer, and y is the height above the central interference maximum.

41. In single slit diffraction, you can use this equation to find the intensity as a function of the angle.

42. For two sources of waves, this equation finds the phase angle between them, depending on the location of the point where you measure the interference of the two waves.

43. Thin film destructive reflection

44. Thin film constructive reflection • Recall that is the wavelength in that medium of index of refraction

45. Single-slit diffraction • a is the width of the slit. • This equation gives diffraction minima • To get maxima, replace m with (m+1/2)

46. This equation gives for diffraction, which can then be used to get the intensity of light at various points.

47. Intensity difference caused by single-slit diffraction. • is calculated from a different equation

48. This equation combines the effects of two-slit interference and the diffraction caused by each of the slits independently.

49. Used to find the chromatic resolving power for a diffraction grating

50. This is used to find the resolving power of a small circular hole of diameter D. • is the location of the first minimum.