First 5 weeks formulas Flashcards
1
Q
Electric field of line of charge) + what the r mean
A
2
Q
nothing ur doing good keep up the work
A
:D
3
Q
Electric field sphere of charge
A
same as point charge
4
Q
e field in a capacitor
no E=v/s the one in formula sheet
A
2(a plane of charge)
5
Q
acceleration in an uniform electrical field
A
a=qE/m
6
Q
parabolic trajectories require… (2)
A
comstant acceleration
uniform e field
7
Q
net force on dipole in uniform e field
A
0
8
Q
torque on dipole in uniform electric field
A
τ = (q E sinθ) d = q d E sinθ
or Fdsintheta
9
Q
electric field of dipole in the same y axis
what does r mean
A
10
Q
electric field of dipole in the x axis (Bisecting)
+what does r mean?
A
the x axis
11
Q
in positive work what is the direction of force and displacement
A
force is same direction as displacement
12
Q
electric potential energy formula
A
U=qEs
13
Q
potential of positive charge as it moves… (2)
A
always +
goes to zero
14
Q
conservation of mechanical energy formula with kinetic and potential
A
1/2mv^2-qEx=1/2mv^2-qx
f=i
15
Q
potential energy of two point charge
A
16
Q
vf for a charge moving in uniform E field from rest
A
re arrange this 1/2mv^2-qEx=1/2mv^2-qx
f=I
vi=o. xi=o
17
Q
escape speed is when
A
the speed that gives Em=0
18
Q
work done on a DIPOLEEEEE
A
19
Q
Parabolic trajectory only arise from
A
constant acceleration and uniform E field
20
Q
net force on dipole in uniform field
A
no net force
21
Q
for nonuniform electric field the net force on the dipole is towards what direction?
A
towards the direction of the strongest field
22
Q
work and explain the relationship btwn the variables
force is constant
A
Find dot prduct when force is parallel to the displacement
23
Q
Work by a non constant force formula+explain
A
we caculate work by dividing the path into many small segments of length (dx), finding the work done in each segment and then summing (integrating) from the start of path to end.
24
Q
conservative force
A
work done on an object is independent of the path it took.
25
potential energy can only be defined when
the force is conservative
26
relate potential energy and work for me
| work. initial.final/neg sign apply here rearrgange formula for me
change in potential energy is negative work (initial-final) which then becomes work final-initial
*ignore picture
27
electric potential energy in unifrom E field is equal to...
| Hint u can figure this out from the work formula
28
in a uniform electric field and u project a particle to the plate with same charge, when does it change directions?
U elec= Emechanic
29
Potential energy of 2 point charge formula
| *reminder this is the energy of the susytem not just q or Q
You can think of it as U=qEs
30
2 sphere of charge potential energy formula
same as point charge but r in this case means from the centre of each sphere
31
the potential energy of two charged particle is zero only when
they are infinitely far apart
32
When you do negative work your are____ the potential energy
increasing
33
multiple point charge electric potential energy
| +formula
the sum of potential energy due to all pairs of charges
34
torque for a dipole
t=pXE
35
potential energy of dipole in unifrom E field
36
formula for total work done on a dipole to turn it
37
Formula for potential energy associated to work done on dipole
38
potential difference between two points
voltage
39
potential energy formula with volatge
U=qV
40
electric potential at negative plate
0
41
electric potential in capacitor
| **Not potential energy
reaarange U=qES and U=qV
42
equipotential
a region in space where every point is at the same potential
43
electric potential of charge q (point charge) formula
44
potential energy outside of a sphere formula charged to potential V0
| (2) formulas
Vsphere=R/r (V0)
R=radius
45
Ho do I find potential of a bunch of point charge?
adding the individual potential energies between each pair
46
high potential is which side?
positive side
47
for unifrom E field CHANGE IN V is (2)
| +say one with area in it
-E(delta S)
48
when is V =-Es?
When do we inetragrate V?
When do we use dot product for V?
| Give me the two scenario
Neg when its "change in V"
49
tell me abt sphere potential/E-field
The efield of a sphere inside the sphere is 0 because the potential inside and outside are the same and E=change in V/s and change in V is 0.
50
any excess charges in a conductor in electrostatic equilibrium are
located on the surfae of the codusctor
51
any two points inside the conductor in electrostatic equilibrium are
at the same potential
52
Two conductors that come into contact form a
single conductor so they exchange charges needed to reach a common potential
53
How do battery work?
The chemical reactions in the battery causes a build up of electrons at the anode. This results in an electrical difference between the anode and the cathode. You can think of this difference as an unstable build-up of the electrons. The electrons wants to rearrange themselves to get rid of this difference. But they do this in a certain way. Electrons repel each other and try to go to a place with fewer electrons.
In a battery, the only place to go is to the cathode. But, the electrolyte keeps the electrons from going straight from the anode to the cathode within the battery. When the circuit is closed (a wire connects the cathode and the anode) the electrons will be able to get to the cathode. In the picture above, the electrons go through the wire, lighting the light bulb along the way. This is one way of describing how electrical potential causes electrons to flow through the circuit.
54
EMF
| +what is it not? +What is it?*Apart*. -talk abt neg charge and terminal
-Work done per charge to pull positive and negative charges apart.
-The force on the negative charge from the electric field is in the opposite direction of the electric field, as shown in Figure 6.1.2. In order for the negative charges to be moved to the negative terminal, work must be done on the negative charges.
IT IS is the amount of energy (E) provided by the battery to each coulomb of charge (Q) passing through.
-it is not a force but rather MAXIMIUM potential difference that creates an electric field that exerts force on charges, causing current. We thus use the name electromotive force
55
Terminal voltage
the potential difference across the terminals of a load when the circuit is turned on
56
Total potential difference for battery in series
57
The Q and V in capcitor equations are awalys
positive
where Q is the magnitude of the charge on each capacitor plate, and V is the potential difference in going from the negative plate to the positive plate. This means that both Q and V are always positive, so the capacitance is always positive.
58
The amount of charge on a capacitance is determined by
| +What is capacitance determined by?
The potential difference, and property of the electrode called capacitance Q=CV
capacitance is determoned by geometry of electrodes
59
Parallel plate capacitor charge formula
Combine: V=Ed and E=Q/e0A
60
Capacitance of parallel plate capacitor:
COmbine charge formula with C=Q/deltaVc
61
Relationship between current, lightbub and capacitor charging
electrons flow in the wires until the capacitors are charged. Once they are charged, no current will flow through and the light bulb would turn off.
62
cuurent flow when charging a capacitor
| picture
63
capacitor charges until
64
How are parallel circuits connected?
Top to top
bottom to bottom
65
How are series circuits connected
end to end in a row
66
parallel capacitor as in side by side have ------ potential difference between the two electrode
| Why?
the same
67
If capacitor C1, C2 and C3 are in parallel, their equivalent capacitance is
68
voltage in a series circuit compared to battery source
The voltage of the battery is the sum of all voltage of the components in a circuit.
69
series capactitors have the same -----as-----
charge on each
70
series capactitors have the same -----as-----
the same current as there is only one path to follow
71
replacing two series capacitor with an equivalent capacitor. What is diff/the same with the charge and voltage?
72
replacing two parallel capacitor with an equivalent capacitor. What is diff/same with the charge and voltage?
73
equivalent capacitance in series circuit
74
Explain how to set up equvalent capacitor equation for series circuit
So we know the charge is the same on every capacitor so for equavalent capacitor, the charge is the same as all the individual capacitor. Then since C=Q/V you find V. The V should be the source of the battery voltage as the sum of the voltage drops in a series circuit equals the total source voltage.
75
Explain how to set up equvalent capacitor equation for parallel circuit
C=Q/V
Q= Q1+Q2+Q3.....
V is the same as the individual parallel circuits
76
capacitance potential energy/ energy stored formula (2)
| The two formulas
77
When do you use U=qV and U=1/2cV^2?
When working with capacitors, you use U=1/2qV. U=qV is used when looking at the potential energy of a charge in a point in space.
78
power in terms of Energy and time
P=E/T
79
tell me which two equation can you use to find capacitance value of parallel capacitor with enot, d and A included
Use C=Q/V
Sub V as Ed
Rearrange and Sub Q in with E=n/enot which is E=Q/Aenot
80
electric field for dipole on y axis (same axis) no the y3 one the one where r is not bigger then length
+What does S mean?
+What does q mean?
where S is distance between the two dipole
q=charge of the dipole you can multiply it into the equation and sub in values if the two point charge in dipole r diff
81
Electric field formula with V and s
82
If Equipotential lines are closer to each other at a region, it means ....
the electric field is strong at that region
83
Electric field is------ in a region where potential isnt changing
0
84
What is the energy conversion between a capacitor that is wired with a battery and then discharged to make a bulb shine?
Potential energy in capacitor transform into kinectic energy to make the charges move and make a current
85
Electrical Potential energy = kQq/r when you put the values of the charges into the formula, you must ...
include the signs ( positive or negative).
