5. Electrostatics

Question 1

Coulumb’s Law vs electric field formula vs electrical potential energy formula vs electrical potential formula vs potential difference formula vs dipole moment formula vs electric torque formula

Answer 1

F = (kQ1Q2)/r^2 aka electric/electrostatic force, can be either pos or neg vs E=F/q=kQ/r^2 vs U=(kQq)/r vs V=U/q=(kQ)/r vs deltaV=Wab/q vs p=Qd or V=(kqd)/r^2*cos(theta) vs tau=pEsin(theta)

Question 2

Charge of a p+ and e-

Answer 2

1.6E-19 C

Pos for proton, neg for electron

Question 3

How are electric field vectors determined?

Answer 3

Pretend a pos test charge is moving thru a source charge. If source is pos, pos test charge will move outwards; if source is neg, pos test charge will move inwards
Electric field’s direction = direction of force if a pos test charge was in that position

Question 4

Know how force of pos/neg test charge will move in an electric field

Answer 4

Pos test charges move with same electric field vectors, neg test charges move opposite of vectors

Question 5

A decrease in electrical potential energy means what?

Answer 5

Increase in stability. THIS IS WHAT YOU WANT

Question 6

Why will potential difference be neg?

Answer 6

This happens spont with pos/neg charges moving from high to low/low to high electrical potential. This results in dec electrical potential energy WHICH IS INC IN STABILITY

Question 7

Remember what an electrical dimple looks like

Answer 7

Dumbell

Question 8

Why is static electricity/static charge buildup better in drier air?

Answer 8

Lower humidity allows charges to become and remain separated more easily

Question 9

Conductor vs insulator

Answer 9

Can evenly distribute e- across their surface b/c nuclei of conductors have free e- roaming around vs don’t distribute e- across their surface b/c nuclei of insulators have e- really close to them

Question 10

Law of conservation of charge

Answer 10

Charge cannot be created or destroyed

Question 11

What’s the direction of an electric field? How is it formed?

Answer 11

From pos charge to neg charge

B/w 2 oppositely charged plates

Question 12

Formula to find force in electric field

Answer 12

F = qE, where q = charge and E = electric field

Question 13

Is an electric dipole a vector?

Answer 13

Yep

Question 14

If you have cat/anions w/ diff magnitudes at fixed positions, how do you know which direction ions will move after it’s released from fixed position?

Answer 14

magnitude trumps attraction/repulsion; use resultant vector formula too