Potential

Question 1

What types of forces are gravitational and electric forces?

Answer 1

Conservative Forces

Question 2

Why are gravitational and electric forces conservative forces?

Answer 2

They have fields that can store energy in the form of potential energy.

Question 3

How do we know a conservative force exists?

Answer 3

A conservative force exists only if there exists some potential energy function U(r).

Question 4

What is related to the work done by a conservative force?

Answer 4

The change in the potential energy of the system.

Question 5

Formula for work with a constant force

Answer 5

W = F • ds (all vectors)

Question 6

naag

Answer 6

Nature abhors a gradient

Question 7

a particle released in a field moves in…

Answer 7

moves in the direction of decreasing potential.

Question 8

Femtometer

Answer 8

10^-15

Question 9

positron

Answer 9

Same characteristics as electron, but positive

Question 10

∆V

Answer 10

Potential Difference

Question 11

Potential is a property of what?

Answer 11

The generating charge only.

Question 12

What type of quantity is ∆V?

Answer 12

Scalar quantity, that exists even without a test charge experiencing it.

Question 13

Units of ∆V

Answer 13

J/C = Volts

Question 14

E field lines point in which direction?

Answer 14

They point in the direction of decreasing potential.

Question 15

Alpha particle

Answer 15

Helium Nucleus, particle with 2e charge (2 protons)

Question 16

Equipotential Surface

Answer 16

A collection of points with the same electric potential.

Question 17

Capacitance dependent on which type of factors?

Answer 17

Geometric factors only, not dependent on battery

Question 18

What has to happen for a capacitor to be charged?

Answer 18

The first charge enters the plate easily, but afterwards, an external agent (the battery) must do positive work to force another charge on the battery. The work (energy) is stored in the electric field as potential energy. The work done is not constant, but varies with q(t)

Question 19

Energy density

Answer 19

u

Question 20

What happens to charge when the capacitor plates are separated further without a battery?

Answer 20

It stays the same, nowhere to go.

Question 21

Battery does what to a capacitor when attached?

Answer 21

It maintains a constant potential.

Question 22

Dielectric

Answer 22

Non-conducting material inserted between capacitor plates to control capacitance and the separation of plates (d)

Question 23

Dielectric constant

Answer 23

intrinsic property of plate material, not geometry. (kappa)

Question 24

What does it mean for a dielectric to break down?

Answer 24

It will no longer function as an insulator, to form a conducting path between the plates.

Question 25

dielectric strength

Answer 25

The maximum electric field that a material can withstand without breakdown is called the dielectric strength [V/m].

Question 26

Maximum potential difference across a ppc is…

Answer 26

∆Vmax = Emax * d

Question 27

When will a dielectric breakdown?

Answer 27

∆V > ∆Vmax

Question 28

Inserting a dielectric in between the plates of a capacitor does what to potential difference?

Answer 28

It limits the maximum potential difference that can be applied to the plates to some ∆Vmax.