ELECTRICITY AND MAGNETISM Flashcards
e=elementart charge= charge of a single atomic particle= 1.6x10^-19
e= 1.6x10^-19 COLOUMBS e-= -1.6x10^-19 COLOUMBS p+= +1.6x10^-19 COLOUMBS
1 coulomb = ?
6.24x10^18 atomic particle
# of electron = # of protons = called? # of electron ≠ # of protons = called? more protons = called? more electron = called?
neutral atom
charged atom/ ION
cation
anion
when 1 coloumbs charge or 6.24x10^18 electrons passes through an imaginary cross section drifting in the same velocity, the flow of charge or current is said to be?
1 AMPERE
1 ELECTRON PASSING THROUGH A CONDUCTOR HAS A CHARGE OF?
1.6X10^-19
CURRENT FORMULA? IN TERMS OF CHARGE.
I= Q/A= COULOMBS / SECOND
identify the current equivalent of the ff.
considered dangerous, can cause temporal paralysis ______
severe shock _______
fatal_______
> 10mA
> 50mA
> 100mA
what are the two types of electricity
static and dynamic electricity
difference of STATIC AND DYNAMIC ELECTROCITY
STATIC IS: STATIONARY TRANSFER OF ELECTRICITY IS ONE AT A TIME TRAVELS IS AIR OCCURS ON OPEN CIRCUIT ALSO CALLED, ELECTRIC FLUX
DYNAMIC: MOVING TRANSFER IS CONTINUOUS. "CYCLE" TRAVELS THROUGH CONDUCTORS OCCURS IN CLOSED CIRCUIT ALSO CALLED CURRENT
FORULA OF COULOMBS LAW THAT IS SIMILAR TO THE GRAVITATIONAL LAW OF NEWTON
Fs=k(q1q2)/r^2 = electrostatic law = electrostatic force
q= charges
k=proportionality constant) = 9X10^9 Nm^2/C^2 (newton, meter, coulomb)
ε0= 8.854x10^-12 F/m (Farahd per meter)
ε0= vaccum permittivity
states that: The net outward normal electric flux through any closed surface is proportional to the total electric charge enclosed within that closed surface divided by the permittivity.
gauss law, gauss’ flux theorem
Φelectric or = Ψ = Q/ε0 = electric flux
electrostatic force VS electric field strength/intensity
electric field strength/intensity is the electrostatic force felt by a test charge from a source charge at a certain distance.
{Q= source charge | q= point charge}
electric field strength/intensity
electric field strength = E = ξ = (Fs/q)
can also be derived to;
ξ= kQ/r^2
ξ= N/C or V/m (voltage over meter/ newton over coulomb)
units of the following k=? Q or q = ? ξ = ? voltage = V = (by joules) =? I = current by time= ?
k=Nm^2/C^2 Q = coulomb r = meter ξ = N/C or V/m V= J/C I= Q/t
prove that ξ is N/C or V/m
ξ = kQ/r^2 = [(Nm^2/C^2)(C)/ (m^2)] = Nm/Cm = J/Cm
[since J = Nm = ((Kgxm)/s^2) X m = Kgm^2/s^2 ]
and since, V= J/C then,
J/Cm = V/m
V/m = N/C
SINCE ξ=V/m we can say that ξ=V/r (since r is in meter). transferring values will give result to V=ξr. PROVE THAT [ V = ∆Pe/q ]
V = ξr = Fs(r)/q (since we know that ξ =Fs/q) = W/q
(W= Fs x r since, force X distance = work)
= ∆Pe/q (becuase W is the change in potention energy)
the magnitude of a magnetic, electric, or other flux passing through a unit area.
FLUX DENSITY
FLUX DENSITY FORMULA BY FIELD STRENGTH
flux density = D = ξε0 = Ψ/A (flux/area)
Voltage can be presented/equated as:
V= W/Q = J/C
MAGNETIC FLUX LINE CAN ALSO BE CALLED
LINE OF FORCE
MEASUREMENT OF LINE OF FORCE
MAXWELL (MX)
signified GROUP OF LINES WHERE, and it’s equivalent in terms of maxwell
WEBBER (WB)
1WB = 1x10^8 MX
is the measure of magnetization that a material obtains in response to an applied magnetic field.
or how easily can a magnetic field be be set up in a material
permeability ( μ)
Unit:
Webber over Ampere meter
W)/(A)(m
magnetic counter part of resistance….
reluctance (FANCY R) (R)
WITH UNIT 1/HENRY
formula for reluctance
R=reluctance
R= s l/A (s=reluctivity)
R =l / μA (μ= permeability)
if resistance is the opposite of conductance and reluctivity is the opposite of permeability, what is the opposite of reluctance?
PERMEANCE
(FANCY P)
=(P)
-PROPERTY OF A MATERIAL TO ALLOW MAGENTIC FLUX TO BE ESTABLISED IN A MATERIAL
WHERE P=1/R
SO UNIT OF P = (HENRY)
RATIO OF PERMEABILITY OF A MATERIAL WITH THAT OF FREE SPACE
RELATIVE PERMEABILITY (μr)
μr = μ/μ0
where μ0 = 4πx10^-7 H/m
TYPE OF MAGNEETIC MATERIALS, GIVE EXAMPLE OF EACH AND GIVE THEIR μr
NON MAGNETIC=
AIR: μr =1
DIMAGNETIC=
COPPER: μr < 1
PARAMAGNETIC=
ALUMINUM μr > 1
FERROMAGNETIC=
IRON μr >= 1
(highed magnetic, 100X or 1000X more than free space)
* can retain magnetism even after magnetic field is removed.
depine susceptibility
amount by which relative permeability differs from unity (1) or free space,
** HAS NO UNIT
Xm = μr - 1
SI unit for flux is?
webber Φ
flux density (B) is denoted as. and has unit _?
of flux lines / unit Area
Flux density with unit Tesla (T) = Wb/m^2
Flux density with unit Gauss (G) = Mx/cm^2
ways to dislodge electron
thermionic emmision
photoelectric effect
triboelectric efffect - (friction)
PRNCET MEANS??
PROTON RUTHERFORD
NEUTRON CHADWICK
ELECTRON THOMPSON
electric flux Φe value when line of foce is along/perpendicular/angled to the area
Φe= EA (PERPENDICULAR) Φe= EA COSθ (ANGLED) Φe= 0 (ALONG MEANING THE LINE OF FORCE GRAZES THE AREA AND NOT CROSS IT ANYHOW)
magnetic field around current carrtying wire
left hand screw rule is for the _____
right hand screw rule is for the ___
electron flow - left
conventional - right
(THUMB IS DIRCTION OF CURRENT, OTHER IS THE DIRRECTION OF THE MAGNETIC FIELD)
direction of current iN solinoid OR COIL ?
USE right hand screw rule
where thumb is flux, and other is current flow.
