Electrostatics

Question 1

how do you describe the electric field inside a charged parallel plate capacitor ?

Answer 1

Electric field is constant and perpendicular to the plates.

Question 2

Describe the electric potential in a parallel plate capacitor ?

Answer 2

Electric potential increases linearly from the negative to the positive plate.

Question 3

how do electric field lines point towards charges ?

Answer 3

Electric field lines point AWAY from positive charges, Toward negative charges.

Question 4

what does voltage also signify ?

Answer 4

V= Potential Difference

Question 5

What happens to charge and capacitance with a dielectric between isolated conductors ?

Answer 5

The presence of a dielectric between two isolated conductors carrying equal but opposite charges cannot change the magnitude of the separated charge, but it does INCREASES the capacitance.

Question 6

What is the formula for change in Electric PE ?

Answer 6

change PE ^E = q x change in electric potential = qV

Question 7

What is work done by electric field?

Answer 7

W by E = - change in Electric potential energy

Question 8

What is the elementary charge (smallest possible unit) ?

Answer 8

e = 1.6 x 10^-19 C

Question 9

What is electrostatic Force equation ?

Answer 9

FE = K |Q||q|/ r^2

Question 10

what is value of k (dielectric constant) in electrostatics ?

Answer 10

k = 9 X 10^9 N x m ^2/ C^2

Question 11

What is formula of electric field ?

Answer 11

E= Electric force/ charge (q)
E= FE/q

Question 12

What is electric field from point charge ?

Answer 12

E = k |Q|/r^2

Question 13

What is unit for electric potential ?

Answer 13

J/C or (Volt)

Question 14

What is formula for electric potential form point charge ?

Answer 14

electric potential = k Q/r

Question 15

What is the unit for electric charge?

Answer 15

Coulombs

Question 16

What is unit for electric field ?

Answer 16

N/C (or V/m)

Question 17

What is equation for capacitors (conducting surfaces separated by insulator)

Answer 17

C= k eo A/d
k : dielectric
Eo : characteristic of insulator
D: distance between surfaces

Question 18

What is the unit for Capacitors?

Answer 18

C= Farads

Question 20

What is formula for charge on capacitor ?

Answer 20

Q = CV

Question 21

What is formula for energy stored by capacitor ?

Answer 21

PE cap= 1/2 QV= 1/2 CV^2= Q^2/2C

Question 22

What is formula for electric field on a capacitor ?

Answer 22

V = Ed

or E= V/d

Question 23

What is conductor ?

Answer 23

conductor: material in which charges move freely

Question 24

What happens when you apply potential difference (voltage) to conductor ?

Answer 24

apply voltage (potential difference) allows net movement of charge (current)

Question 25

What is a current in conductor ? What is formula and units for current ?

Answer 25

Current: flow rate of charge I = change in Charge/ time I = Q/t units Amperes (A) : C/s

Question 26

What is formula for Ohms' law ?

Answer 26

V = IR

Question 27

What is resistivity ?

Answer 27

resisitivity: how much a material opposes flow of charge through it

Question 28

What is resistance ?

Answer 28

Resistance ; how much an OBJECT opposes flow of charge through it

Question 29

What is formula for Resistance ? what is the unit?

Answer 29

R= p (resistivity) L/A units : ohm

Question 30

What is the Req equation for resistors in series ? What do resistors have in common

Answer 30

Req= R1 + R2 + R3.... (req series > R1, R2, R3) resistors in series have Same CURRENT throughout

Question 31

What is Req equation for resistors in parallel ? What do resistors have in common for parallel ?

Answer 31

Req= 1/R1 + 1/R2 + 1/R3 restores in parallel have Same VOLTAGE

Question 32

what happens when you put formulas for electric field and electric potential together ?

Answer 32

Electric field : E = k Q/ r^2 electric potenital = k Q/r hence together = electric potential / r ( kq/r) / (r) = same as kq/r^2

Question 33

what is equation for change in KE for absence of nonconservative forces ?

Answer 33

Change in KE= - change in PE

Question 34

What is formula for kinetic energy

Answer 34

KE = 1/2mv^2

Question 35

What happens to voltage if two capacitors are in parallel?

Answer 35

. if two capacitors are in parallel, and voltages in parallel must be the same)

Question 36

How do you define equilibrium for a capacitor ?

Answer 36

Equilibrium is established when the potential difference, or voltage, is the SAME across each capacitor

Question 37

what is another formula used to calculate potential energy for capacitors?

Answer 37

PE =1/2QV= Q^2/2C or PE= 1/2CV^2