Agenda Today –Chapter 24 (Finish Fri & Start 25) HMWK Due Fri Return Quiz Friday Reading –Finish ch. 24 by Friday –Skim 25 (at least last page) Friday –Read 25 by Monday

Simplest Form: || Plate Apply Voltage Across Parallel Plates V = Ed E (plate) =    E (Between) =     = Q/A Infinite just approximation E = Q/(A  0 ) V = Ed V = Qd / (A  0 )

Simplest Form: || Plate Apply Voltage Across Parallel Plates V = Qd / (A  0 ) Capacitance = Ability to store Charge from V Q = V C [C is capacitance] V = Q / C || plate: C = A  0 /d Examine parameters Geometric & material only, no field dep.

Energy Storage: Capacitor Consider how much energy it takes to move charges from one plate to another “Assemble” Charges Work done in moving charges stored as Potential Energy

Energy Storage: Capacitor Can Apply Top Equation to Bottom Mix & Match, Q,V,C As usual, ½  Integration

Other Geometries Spherical, other all have different formulas for capacitance Universal: –C depends only on dielectric & geometry –Q = VC –PE = Q 2 /2C

|| Plate Combinations C = A   /d How does capacitance change if we go from One…

|| Plate Combinations C = A   /d How does capacitance change if we go from One… To Two capacitors attached like this? Does V Change? Does Q Change? Depends on outside Capacitance internal!

|| Plate Combinations C = A   /d How does capacitance change if we go from One… To Two capacitors attached like this? Is Same as…

|| Plate Combinations C = A   /d How does capacitance change if we go from One… To Two capacitors attached like this? Is Same as… Twice the Area Twice the capacitance..

|| Plate Combinations C = A   /d How does capacitance change if we go from One… To Two capacitors attached like this? Comment on the charge at these 2 points? Must be Equal & opposite? How about must be same? So Effective Capacitor looks like….

|| Plate Combinations C = A   /d How does capacitance change if we go from One… To Two capacitors attached like this? Effective Distance between plates doubled Capacitance halved

Series & Parallel First Look Series Capacitors Capacitance Reduced Parallel Capacitors Capacitance Increased

Future Next Week Monday: Ch.25 Need to Miss Wed? –Class Canceled or Sub? –Sub = Quiz Wed, Lecture & Lab Tues –No Sub = Skip Lab, Quiz & Lecture Tues Quiz on Problem from CH

What? Alternative Energy Research New (hopefully) multi-year investigation Exploring new materials for use in hydrogen energy storage and solar power –Chemistry & Chemical Bonding –Nanoscience measurement and analysis –Materials Science –Engineering: Design, Implementation, and Development –Integration with future and current teachers –Integration with science policy

Who? Students interested in engineering –Electrical, materials, systems –Good with hands, not afraid of electricity –Willing to learn CAD design Students interested in Experimental Science –Chemistry/Physics Mixture –Materials UNI, Nanostructures formed here –Analysis (SEM, AFM, STM) & Feedback –Understand, Predict, Create Novel materials Students interested in Science Education –Perform Experimental Research –Work with junior high & high school teachers –Develop curriculum & research

How Many? Looking for another 2 or 3 students –Summer & perhaps beyond Need: AFM Operator Nanoscale Objects Several atoms high (<10) Template for High Efficiency Solar Cell

How Many? Looking for another 2 or 3 students –Summer & perhaps beyond Need: SEM/EDX Operator? Microstructure Characterization Chemical Information Also

How Many? Looking for another 2 or 3 students –Summer & perhaps beyond Need: UHV /Elecronics Engineer –Begin by implementing, Work towards Design

Modeling Work towards understanding of fundamental science Experience with programming a + Understand phenomena