ELECTRICITY AND MAGNETISM Flashcards

1
Q

e=elementart charge= charge of a single atomic particle= 1.6x10^-19

A
e= 1.6x10^-19 COLOUMBS
e-=    -1.6x10^-19 COLOUMBS
p+=   +1.6x10^-19 COLOUMBS
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2
Q

1 coulomb = ?

A

6.24x10^18 atomic particle

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3
Q
# of electron = # of protons = called?
# of electron ≠ # of protons = called?
more protons = called?
more electron = called?
A

neutral atom

charged atom/ ION

cation

anion

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4
Q

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?

A

1 AMPERE

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5
Q

1 ELECTRON PASSING THROUGH A CONDUCTOR HAS A CHARGE OF?

A

1.6X10^-19

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6
Q

CURRENT FORMULA? IN TERMS OF CHARGE.

A

I= Q/A= COULOMBS / SECOND

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7
Q

identify the current equivalent of the ff.
considered dangerous, can cause temporal paralysis ______

severe shock _______

fatal_______

A

> 10mA

> 50mA

> 100mA

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8
Q

what are the two types of electricity

A

static and dynamic electricity

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9
Q

difference of STATIC AND DYNAMIC ELECTROCITY

A
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
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10
Q

FORULA OF COULOMBS LAW THAT IS SIMILAR TO THE GRAVITATIONAL LAW OF NEWTON

A

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

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11
Q

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.

A

gauss law, gauss’ flux theorem

Φelectric or = Ψ = Q/ε0 = electric flux

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12
Q

electrostatic force VS electric field strength/intensity

A

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}

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13
Q

electric field strength/intensity

A

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)

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14
Q
units of the following
k=?
Q or q = ?
ξ = ?
voltage = V = (by joules) =? 
I = current by time= ?
A
k=Nm^2/C^2
Q = coulomb
r = meter
ξ = N/C or V/m
V= J/C
I= Q/t
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15
Q

prove that ξ is N/C or V/m

A

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

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16
Q

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 ]

A

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)

17
Q

the magnitude of a magnetic, electric, or other flux passing through a unit area.

A

FLUX DENSITY

18
Q

FLUX DENSITY FORMULA BY FIELD STRENGTH

A

flux density = D = ξε0 = Ψ/A (flux/area)

19
Q

Voltage can be presented/equated as:

A

V= W/Q = J/C

20
Q

MAGNETIC FLUX LINE CAN ALSO BE CALLED

A

LINE OF FORCE

21
Q

MEASUREMENT OF LINE OF FORCE

A

MAXWELL (MX)

22
Q

signified GROUP OF LINES WHERE, and it’s equivalent in terms of maxwell

A

WEBBER (WB)

1WB = 1x10^8 MX

23
Q

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

A

permeability ( μ)

Unit:
Webber over Ampere meter
W)/(A)(m

24
Q

magnetic counter part of resistance….

A

reluctance (FANCY R) (R)

WITH UNIT 1/HENRY

25
formula for reluctance
R=reluctance R= s l/A (s=reluctivity) R =l / μA (μ= permeability)
26
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)
27
RATIO OF PERMEABILITY OF A MATERIAL WITH THAT OF FREE SPACE
RELATIVE PERMEABILITY (μr) μr = μ/μ0 where μ0 = 4πx10^-7 H/m
28
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.
29
depine susceptibility
amount by which relative permeability differs from unity (1) or free space, ** HAS NO UNIT Xm = μr - 1
30
SI unit for flux is?
webber Φ
31
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
32
ways to dislodge electron
thermionic emmision photoelectric effect triboelectric efffect - (friction)
33
PRNCET MEANS??
PROTON RUTHERFORD NEUTRON CHADWICK ELECTRON THOMPSON
34
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) ```
35
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)
36
direction of current iN solinoid OR COIL ?
USE right hand screw rule where thumb is flux, and other is current flow.