Flashcards in ch 5 - Electrostatics and Magnetism Deck (20)

Loading flashcards...

1

## electrical potential of dipole

###
V=(kq)/rsub1 - (kq)/rsub2 = (kq(rsub2 - rsub1))/rsub1rsub2

At greater distance: V = ((kqd)/rsquared) x costheta;

d = distance between +q and -q (source charges); rsub1 = distance between the chosen point in space and +q; rsub2 = distance between said point and -q

2

## dipole moment (p)

### SI units are C x m: p = qd

3

## perpendicular bisector of the dipole

### plane that lies halfway between +q and -q. Because the angle between this plane and the dipole axis is 90 degrees (and cos 90 = 0) the electrical potential at any point along this plane is 0.

4

## electric dipole

### result of two equal and opposite charges being separated a small distance (d) from each other; can be transient or permanent

5

## magnitude of the electric field on the perpendicular bisector of the dipole

### E = 1/(4pi x epsilonsub0) x p/r^3

6

## electrostatic constant (k)

### 8.99 x 10^9 (N x m^2)/C^2

7

## net torque on dipole

### T = pE sintheta where p = magnitude of dipole moment (p = qd), E = magnitude of uniform external electric field, and theta = angle the dipole moment makes with the electric field; this will cause dipole to reorient itself so that its dipole moment (p) aligns with the electric field E

8

## equipotential lines

### lines on which the potential at every point is the same; potential difference bt any two points on an equipotential line is zero

9

## SI unit for magnetic field strength

### tesla (T) 1 T = 1 (N x s)/(m x C); or when smaller measured in gauss. 10^4 gauss = 1 T

10

## diamagnetic materials

### made of atoms with no unpaired electrons and that have no net magnetic field; can be called weakly antimagnetic

11

## Paramagnetic materials

### have unpaired electrons; weakly magnetized in the presence of an external magnetic field, aligning the magnetic dipoles of the material with the external field (ex aluminum, copper and gold)

12

## Ferromagnetic materials

### have unpaired electrons and permanent atomic magnetic dipoles that are normally oriented randomly so that the material has no net magnetic dipole. will become strongly magnetized when exposed to a magnetic field or under certain temps (iron, nickel and cobalt)

13

## for infinitely long and straight current-carrying wire, equation for magnitude of magnetic field

### B = (fancy u sub 0 x I)/(2pi r) I (i) = current in the wire; r = perpendicular distance of the current from the wire; B = magnetic field; fancy u sub 0 = permeability of free space (4pi x 10^-7 (T x m)/A)

14

## right hand rule for straight wire magnetic fields

### point thumb in direction of current and wrap fingers around current-carrying wire. Fingers mimic circular field lines curling around wire

15

## magnitude of magnetic field at center of circular loop of current carrying wire

### B = (fancy u sub 0 x I)/2r r = radius of loop; fancy u sub 0 = permeability of free space (4pi x 10^-7 (T x m)/A); B = magnetic field; I = current in wire

16

## Lorentz force

### sum of the electrostatic and magnetic forces acting on charges in magnetic field

17

## magnetic force

### F sub B = qvB sin theta; q = the charge; v = magnitude of velocity, B = magnitude of magnetic field; theta = smallest angle between the velocity vector v and the magnetic field vector B; unit is N

18

## right-hand rule of magnetic forces

### to determine direction of the magnetic force on moving charge; position right thumb in direction of the velocity vector; put fingers in direction of magnetic field lines; palm points in the direction of the force vector for a positive charge, while back points in direction of force vector a negative charge

19

## For a straight wire, magnitude of force created by external magnetic field

### F sub B = ILB sin theta; I (i)= current; L = length of wire in the field; B = magnitude of magnetic field; theta = angle between L and B

20