Study with the several resources on Docsity
Earn points by helping other students or get them with a premium plan
Prepare for your exams
Study with the several resources on Docsity
Earn points to download
Earn points by helping other students or get them with a premium plan
An overview of electrostatics, including conductors and insulators, charging by conduction and induction, coulomb's law, and electric fields. It covers the concepts of charges, coulomb's constant, electric field strength, and electric field lines.
Typology: Study notes
1 / 6
This page cannot be seen from the preview
Don't miss anything!
Conductors – one or more electrons from each atom in solid can move freely though body conducting electric charge (metals)
Insulators – electrons are strongly bound to nuclei inhibiting electric charge (plastics, glass, rubber)
Charging by conducting – transfer of charge between two objects through contact – objects have same charge
Charging by induction – object charged by second object without touching – objects have opposite charge
Coulomb’s Law: The magnitude of the electric force between two electric point charges is proportional to the product of the two charges (Q 1 and Q 2 ) divided by the square of the distance of between them (r)
1 2 2
F k r
SI unit for charge: Coulomb “C”
where
2 9 2
1 N m k 8.988x 4 π εo C
2
2 12 N m
8.85x
ε (^) o , permittivity of free space
This force is attractive for charges of opposite sign and repulsive for charges of like sign. The direction of this force is along the line joining the two point charges.
NOTE AGAIN: Acquisition of positive and negative charges between objects results from transfer of electrons
Charges on objects (ebony, glass, etc.) are integral numbers of
Charges produced by rubbing objects (ebony, glass) are on the order of a microcoulomb (1 C=1x10-6^ C)
Total force on a charge, q, is the vector sum of forces resulting from other charges ( Superposition of Forces )
net ^1 ^2 ^3
r
Q 1 Q (^2)
q
+q
-q
