{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

# lecture2 - Electric Field Coulombs Law Electric Field...

This preview shows pages 1–7. Sign up to view the full content.

Electric Field Coulomb’s Law Electric Field – definition Text sections 23.3, 23.4 Practice: Chapter 23 , problems 3, 7, 11, 13, 15 Coulomb’s Law Point charges exert forces on each other: 2 1 q q , r r 1 q 2 q r ˆ r F ˆ 2 2 1 r q q k e = 2 2 9 10 988 8 C m N x k e = . (Coulomb’s Law constant) r ˆ is a unit vector parallel to r F F

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

View Full Document
Notes: for point charges only r F r r || 1 q F r 2 q F r 2 1 r F r We also define 2 2 12 0 10 85 . 8 m N C x ε o e k πε 4 1 . (“permittivity of vacuum”) Exercise: L L ° 30 ° 30 m m q q GIVEN : •Identical Masses, m=1.0 gram •Equal charges q •L= 60 cm FIND : q (equilibrium) (How big is a coulomb?)
Quiz: L L m m 2q q/2 What happens to each angle if the charge on the left is doubled, and the other one is halved? (equilibrium) ? ? Example Example : Find: Force (vector) on q 3 , in Cartesian form. C q µ 10 1 = C q µ 20 2 = C q µ 30 3 = 400mm 300mm

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

View Full Document
Electric Field E r Coulomb’s Law: “action at a distance” q ο q Force Field Picture: The “source” charge q produces an electric field in space. The field pushes on the “test” charge q 0 . ? Definition: Electric Field ο q F E r r • A vector • Exists before test charge is introduced

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

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}