# Lecture_07_-_no_quiz_answers - Lecture 7 1/17 Comparing...

This preview shows pages 1–5. Sign up to view the full content.

Lecture 7 1/17 Comparing Electricity and Gravity Electricity Gravity E q r r q q k F 2 2 2 1 ˆ Potential Energy r r q k E ˆ 2 1 V E r q k V 1 V q U 2 g m r r m M G F 2 2 2 1 ˆ r r M G g ˆ 2 1 g r M G 1 2 m U Field from Potential Force Field Potential

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

View Full Document
Lecture 7 2/17 Electrostatic Potential Energy The electrostatic potential energy of a system (relative to ∞) is the (external) work needed to bring the charges from an infinite separation to their final positions. q 1 q 2 q 3 r 13 r 23 r 12 23 3 2 13 3 1 12 2 1 r q q k r q q k r q q k W U ) ( 2 1 3 3 2 2 1 1 V q V q V q U n i i i V q U 1 2 1 In general for n charges: 23 2 13 1 3 12 1 23 3 2 13 3 12 2 1 2 1 r q k r q k q r q k r q k q r q k r q k q U
Lecture 7 3/17 Electrostatic Potential Energy of Conductors Initial charge q and potential V(r) Now add charge dq to sphere R spherical conductor dq r q k dq r V dU ) ( q R Q k V bring in dq from infinity V Q R Q k dq q R k dU U Q 2 1 2 2 0 Total potential energy U to build charge from 0 up to Q q V(r) dq Q V dU V(r) = kq/r

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

View Full Document
4/17 Two parallel planes, 2 m apart, are charged with uniform charge densities 2 and (in C/m 2 ). Respectively as shown. What is the potential difference V B -V A (in volts)? Quiz Question 1
This is the end of the preview. Sign up to access the rest of the document.

## This note was uploaded on 03/14/2012 for the course PHYS 241 taught by Professor Wei during the Summer '08 term at Purdue.

### Page1 / 17

Lecture_07_-_no_quiz_answers - Lecture 7 1/17 Comparing...

This preview shows document pages 1 - 5. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online