Search
Create
Log in
Sign up
Log in
Sign up
Summary TCC
STUDY
Flashcards
Learn
Write
Spell
Test
PLAY
Match
Gravity
Terms in this set (20)
The_______ at some point in space is defined as the electric force F that acts on a small positive test charge placed at that point divided by the magnitude q0 of the test charge:
electric field
E=F/qo
Electric charges have the following important properties:
• Charges of opposite sign attract one another, and charges of
the same sign repel one another.
• The total charge in an isolated system is conserved.
• Charge is quantized.
_____are materials in which electrons move freely._____ are materials in which electrons do not move freely.
Conductors
Insulators
_______ states that the electric force exerted by a point
charge q1 on a second point charge q2 is_____
Coulomb's law
F12= K(q1q2/r^2) r(^)12
where r is the distance between the two charges and r(^)12 is a unit vector
directed from q1 toward q2. The constant ke, which is called the
Coulomb constant, has the value k= 8.99E9 N.m2/C2.
The electric force on a charge q placed in an electric field E
is:
F=qE
At a distance r from a point charge q, the electric field due to the charge is_____________
E=k(q/r^2)r^
where r^ is a unit vector directed from the
charge toward the point in question. The
electric field is directed radially outward
from a positive charge and radially inward
toward a negative charge.
The electric field due to a group of point charges can be obtained by using the superposition
principle. That is, the total electric
field at some point equals the vector sum of the electric fields of all the charges:
E=k(sum)(q/r^2)
The electric field at some point due to a continuous charge distribution
is______
E=k(integral)(dq/r^2)
where dq is the charge on one element of the charge distribution
and r is the distance from the element to the point in question.
_______is proportional to the number of electric field lines that penetrate a surface. If the electric field is uniform and makes an angle (theta) with the normal to a surface of area A, the electric flux through the surface is____
Electric flux
(phi)=EAcos(theta)
In general, the electric flux through a surface is
(phi)= (integral)E.dA
____ says that the net electric
flux (phi) through any closed gaussian
surface is equal to the net charge qin
inside the surface divided by e0:
Gauss's law
phi=(integral)E.dA=qin/eo
Using Gauss's law, you can calculate
the electric field due to various symmetric
charge distributions.
A conductor in (electrostatic equilibrium) has the following properties:
1. The electric field is zero everywhere inside the conductor, whether
the conductor is solid or hollow.
2. If the conductor is isolated and carries a charge, the charge resides
on its surface.
3. The electric field at a point just outside a charged conductor is perpendicular
to the surface of the conductor and has a magnitude o-/eo,
where o- is the surface charge density at that point.
4. On an irregularly shaped conductor, the surface charge density is
greatest at locations where the radius of curvature of the surface is
smallest.
The_____ (delta)V between points A and B in an electric field E
is defined as____
potential difference
(V)=U/q= - (integral a-b) E.ds
The electric potential V=U/q0 is a scalar quantity and has the units of jouls per coulomb, where 1J/C=1V
An_______ is one
on which all points are at the
same electric potential. _______s are perpendicular
to electric field lines.
equipotential surface
When a positive test charge q0 is moved between points A and B in an electric field E , the change
in the potential energy of the charge-field system is
(U)= - qo (integral a-b) E.ds
The potential difference between two points and separated
by a distance d in a uniform electric field E, where s
is a vector that points from A toward B and is parallel to E
, is________
(V)= -E(integral a-b) ds= -Ed
If we define V = 0 at r= infinity, the electric potential due to
a point charge at any distance r from the charge is
V=k(q/r)
The electric potential associated with a group of point
charges is obtained by summing the potentials due to
the individual charges.
The potential energy associated with a pair of point
charges separated by a distance r12 is
U=K(q1q2/r12)
We obtain the potential energy of a distribution of point charges by summing terms like the Equation
over all pairs of particles.
If the electric potential is known as a function of coordinates x, y, and z, we can obtain the components of the electric field by taking the negative derivative of the electric potential with respect to the coordinates. For example, the x component of the electric field is
Ez= -(dV/dX)
The electric potential due to a continuous charge distribution is___
V=k(integral)dq/r
Every point on the surface of a charged conductor in electrostatic
equilibrium is at the same electric potential. The potential
is constant everywhere inside the conductor and equal to its
value at the surface.
;