Card Set Information

2014-05-21 12:27:49
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  1. Describe the shape/direction of electric field lines
    • They radiate outward from + charges and toward - charges (test charge is +)
    • They form various shapes if they are near eachother
  2. What does "F12" mean?
    The force that 1 exerts on 2 (look at it from 2's perspective)
  3. tan/sin/cos?
    • tan = opp/adj
    • sin = opp/hyp
    • cos = adj/hyp
  4. Other useful equations to remember regarding force?
    • F=ma
    • F=mv2/r  (circular motion)
  5. Describe electric potential of charges in a parallel plate capacitor
    charges move from + to - therefore charges that are closer to the + plate have increased potential energy
  6. How do you determine the potential energy of a group of charges? (a system)
    Detrmine the potential energy (Vq = kq1q2/r) for each point and then sum them.  Easy.
  7. How do you determine the difference in energy of something between 2 plates?
    • KE + PE = KE + PE
    • If stopped, KE=0
    • If at the - plate, PE = 0
  8. Describe the equivalent properties (q,V,C) for a capacitor in series.  A resistor? (R, I)
    • qeq=q1=q2=q3
    • V=V1+V2+V3
    • 1/Ceq=1/C1+1/C2+1/C3
    • Req=R1+R2+R3
    • I=I1=I2=I3
  9. Describe the equivalent properties (q,V,C) for a capacitor in parallel. A resistor? (R,I)
    • q=q1+q2+q3
    • V=V1=V2=V3
    • C=C1+C2+C3
    • 1/Req = 1/R1+1/R2+1/R3
    • I=I1+I2+I3
  10. Describe Kirchoff's point rule.
    The sum of current into a junction is equal to the sum of the current out of a junction
  11. How do you perform Kirchoff's loop rule?
    • 1. Choose a direction for I
    • 2. Choose a start point
    • 3. Move along the circuit in a direction, moving back toward point chosen in step 2
    • 4. Use rules for crossing various elements and place into equation
    • 5. Apply loop rule
    • 6. Solve for the unknown
  12. What is internal resistance?
    The resistance WITHIN a battery (should be obvious)
  13. Magnetic field direction?
    Flows from north and into south
  14.   vs    vs  
    • eq1 = long straight wire carrying a current, causing circular magnetic field around it
    • eq2 = loop carrying a current, causing straight magnetic field through center (a=radius of loop)
    • eq3 = solenoid carrying a current, causing straight magnetic field through center (n = #turns/unit length)
  15. symbols for into vs out of page (magnetic field)
    x is into and o is out of
  16. What are the various "right hand rules"
    • For current in a loop: thumb aligns with current and fingers curve to show direction of B field
    • For wire in a B field: I(thumb) B(index) F(middle)
    • For charged particle in a B field: v(thumb) B(index) F(middle)
    • ***remember if charge is negative then reverse direction!
  17. What is the equation for the force of a circular object?
  18. What are the two types of mechanical waves (direction)
    • Transverse: the element moves vertically white the velocity is horizontal
    • Longitudinal: the element AND velocity move only horizontally
  19. What are the characteristics of a wave?
    • frequency (f): # oscillations per second
    • wave length (λ): distance wave travels before it repeats
    • Period (t): time it takes for one cycle to be completed
    • f=1/t
  20. Difference between electromagnetic waves and mechanical waves?
    EM waves do not need a medium to travel
  21. Wave front vs ray? What is their relationship?
    • Wave front: the wave itself (the ripple after throwing a stone)
    • Ray: the direction that the wave travels
    • Wavefronts and rays are always perpendicular
  22. Describe the laws of reflection, refraction, and diffraction
    • *remember- all angles taken between ray and NORMAL of surface
    • reflection: Angle of incidence = angle of reflection
    • Law of refraction: angle of incidence > angle of refraction
    • ray refracts TOWARD the normal
  23. What is the critical angle?
    • When the angle of refraction becomes 90 degrees
    • Anything above is total internal reflection
  24. Describe the reflections of a concave mirror
    • a ray parallel to the principal axis is reflected through F
    • a ray that pass through F is reflected parallel to the principal axis
    • a ray that meets the mirror at the principal axis is reflected at the same angle
    • a ray that passes through O is reflected directly back (180)
  25. What makes an image real, inverted, larger, smaller, etc in a reflection?
    • real/virtual: if the light meets in front of the mirror it is a real image
    • inverted/upright: if the light meets on the opposite side of the principal axis then it is projected from it is inverted
    • larger/smaller: if the light meets at a point PAST the source then it is larger
  26. Describe the light passthrough in a converging lens
    • ()
    • Ray parallel to principal axis passes through focal point on other side
    • Ray passing through principal axis in center of lens continues without refraction (0 change)
    • Ray passing through focal point continues straight on other side
  27. Describe light passthrough in a diverging lens
    • )(
    • Ray parallel to principal axis refracts away from the principal axis so that an imaginary line from the focal point is straight
    • Ray passing through principal axis in center of lens continues without refraction
    • Ray aimed at opposite side F (imaginary line) will come out parallel to principal axis