30_Lec-19

30_Lec-19 - Physics 241 Lecture 19 Y E Kim November 2 2010...

Info iconThis preview shows pages 1–12. Sign up to view the full content.

View Full Document Right Arrow Icon
November 2, 2010 1 University Physics, Chapter 30 Physics 241 Lecture 19 Y. E. Kim November 2, 2010 Chapter 30, Sections 1, 2, and 4
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
November 2, 2010 Physics for Scientists & Engineers, Chapter 30 2 LC Circuits Analysis of LC Oscillations Driven AC Circuits
Background image of page 2
November 2, 2010 3 ± Inductance L of a solenoid as proportionality constant between the flux linkage N ) B and the current i (in analogy to q = CV ): ± The unit of inductance is the henry (H) ± The inductance of a solenoid of length l and area A with n turns per unit length an is given by Review: Inductance 2 [] 1 Tm 1 H 1 A ) ± 2 0 nlA P N ) B Li University Physics, Chapter 30
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
November 2, 2010 University Physics, Chapter 30 4 Review: LR Circuit ± LR circuit L di d t ± iR 0 i ( ) 0 e ² / W 0 V emf / R ± m f ³ ´ ³ ´ // () 1 ² ² = / Circuit connected to emf Circuit disconnected from emf
Background image of page 4
November 2, 2010 University Physics, Chapter 30 5 Review: Energy in Capacitors and Inductors ± Remember that the energy stored in the electric field of a capacitor with charge q is given by ± Remember that the energy stored in the magnetic field of an inductor carrying current i is given by ± To illustrate ´HOHFWURPDJQHWLF RVFLOODWLRQVµ± consider a simple LC circuit containing an inductor L and a capacitor C 2 1 2 E U 2 1 2 B Li
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
November 2, 2010 University Physics, Chapter 30 6 LC Circuit (1) ± The capacitor is initially fully charged and then connected to the circuit ± The energy in the circuit resides solely in the electric field of the capacitor ± The current is zero ± 1RZ OHW·V IROORZ WKH HYROXWLRQ ZLWK WLPH RI WKH FXUUHQW± charge, magnetic energy, and electric energy in the circuit
Background image of page 6
LC circuits (2) Time Evolution November 2, 2010 Physics for Scientists & Engineers, Chapter 30 7
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
November 2, 2010 University Physics, Chapter 30 8 LC Circuits (3) ± The charge on the capacitor varies with time ± Max positive to zero , to max negative , to zero, back to max positive ± The current in the inductor varies with time ± Zero to max positive , to zero , to max negative, back to zero ± The energy in the inductor varies with the square of the current and the energy in the capacitor varies with the square of the charge ± The energies vary between zero and a maximum value
Background image of page 8
November 2, 2010 University Physics, Chapter 30 9 LC Circuits (4)
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
November 2, 2010 University Physics, Chapter 30 10 LC Oscillations (1) Quantitatively: ± We assume a single loop circuit containing a capacitor C and an inductor L and that there is no resistance in the circuit ± We can write the energy in the circuit U as the sum of the electric energy in the capacitor and the magnetic energy in the inductor ± We can re-write the electric and magnetic energies in terms of the charge q and current i E B ± 2 2 11 22 Li ± ±
Background image of page 10
November 2, 2010 University Physics, Chapter 30 11 LC Oscillations (2) ± Because we have assumed that there is no resistance and the electric field and magnetic field are conservative , the energy in the circuit will be constant ± Thus the derivative of the energy in the circuit with respect to time will be zero ± We can then write ± Remembering that i = dq / d
Background image of page 11

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 12
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

Page1 / 33

30_Lec-19 - Physics 241 Lecture 19 Y E Kim November 2 2010...

This preview shows document pages 1 - 12. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online