# ics1sem1block8 teacher packet - Chatsworth High School

Electronics - Devices

Nov 2, 2013 (4 years and 7 months ago)

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Item Ics 1 Sem1 block 8 EM fields

Objective

The
electromagnetic force is one of only four fundamental
forces; the others are the gravitational force
,
strong and
weak nuclear
forces. Many devices,
such as household
appliances,

computers, and equipment for c
ommunication,
entertainment, and transportation,

were developed from
electromagnetic phenomena.

Students should understand

the concepts of motion, forces, and conservation of energy.
Students should be acquainted with b
oth Newton’s law,
Coulomb’s law and that they describe forces that diminish
as the sq
uare of distance.

Understand how Transistors are
used as gates and amplifiers.

Language Objective

Use the vocabulary words appropriately. Explain
the similarities and differences between Electric
and Magnetic fields. Use phrases such as
perpendicular oscillation, direction of motion,
Coulomb’s Law, induction of field, and
transistors appropriately.

D
escribe the potential energy and its connection with the Electric Field of a charged
particle. Use the terms ions, electrons, field, force, inverse and “lines of force” when appropriate.

Copy PH 5 d, e, h, i, j, m

below

PH 5 d

Students know
the
properties of transistors and the role of transistors in
electric circuits.

PH 5 e

Students know
charged particles are sources of electric fields and are
subject to the forces of the electric fields from other charges.

PH 5 h

Students know
changing magne
tic fields produce electric fields, thereby
inducing currents in nearby conductors.

PH 5
I
Students know
plasmas, the fourth state of matter, contain ions or free
electrons or both and conduct electricity.

PH 5 j
*
Students know
electric and
magnetic fields contain energy and act as
vector forc
e fields.

PH 5 m* Students

know
static electric fields have as their source some
arrangement of electric charges.

Period____

Name __________________________

Sign__________________________

Parent/Guardian:
Print_______________________________

Sign________________________________

8.1

Cover sheet

ICS 1 Sem1 Block 8 Physics 5 d, e, h, i, j, m

To be accepted for
grading it must be in order and signed

Please go through the paper work with your student.

Test and packet due on 12/3 odd 12/4 even

Assignment list

8.1
Cover

8.2
WCW

8.3.1
Standards
fill in blank

8.3.2

Standards
Questions

8.4
Vocabulary

8.5.1 notes transistors

8.5.2 notes Charge and E
-
field

8.5.3 notes EM induction

8.5.4 notes Plasma

8.6.1 ws Transditors

1sv

2 fdg

8.6.2 ws Charge and E
-
field

1

Static Electricity
Lightning

2

Static Electricity crossword

8.6.3 ws EM induction

1 Electric Current

2 What is magnetism?

3 Magnetic field of Earth

8.6.4 ws Plasma

1sv

2 fdg

8.7
Study guide
and CST prep

Item Ics 1 Sem1 block 8 EM fields

8.2 WCW

student fill out answers

Warm
-
up 1

Newton’s law

Coulomb’s law

If I
double

the distance between the objects
,

the force decreases by
quarter
. If I

half

the distance between the objects
,
the

force
in
creases by
quadruple
.
If
I

double

each of the
mass
es

or charge
s’

of

the objects
,

the force increases
by
quadruple
. If
I
half

each of the
mass
es

or charge
s’

of
t he

object s
,

t he force decreas es by
quart er
.

Critical thinking 1

1.6×10

19

joule

(symbol J). By definition, it is the amount
of energy gained by the charge of a single
electron

moved
across an
electric

potential difference

of one
volt
. Thus it is
1
volt

(1
joule

per
coulomb
, 1 J/C) multiplied by the
electron charge

(1 e, or 1.
602176565(35)×10

19

C
).

Wrap
-
up 1

The subject of energy transport by waves is important:

(1)
Charge

occurs in d
efinite, discrete amounts

(2) C
harge comes in
two

varieties:

posit
ive and
negative, neutral

(3) The smallest amount of observable charge is the charge
on an
electron

(or a proton).

Warm
-
up 2
electromagnetic field
,
EMF

or
EM field

is produced by moving
charged
objects
. The electric field is produced by
stationary
charges

and the magnetic field
by
moving
charges

currents

;
i.e. the
two
are the sources of the field.

Critical thinking 2
The behavior of the electromagnetic field can be
resolved into four differen
t parts of a loop,

t
he electric and magnetic fields

1

are
generated

by electric charges

2

interact

with each other

3

produce

forces on electric charges

4

the electric charges
move

in space

Wrap
-
up 2

1
charged
particles
generate

electric, (in motion
magnetic fields
)

2
fields
interact

with each other

3
changing electric field acts like a
current
,
generating 'vortex' of magnetic
field

4
Faraday induction
:
changing

magnetic field induces (negative) vortex of
electric field

5
Lenz's law
: negative feedback
loop

between electric and magnetic fields

6
fields act upon particles
,

-

Lorentz force: force due to electromagnetic field

-

electric force: same direction as electric fie
ld

-

magnetic force:
perpendicular

both to magnetic field and to velocity of
charge

7
particles move current is movement of particles

8
particles generate more electric and magnetic fields; cycle
repeats

Warm
-
up 3

Plasma
-
state of matter

similar to
gas
, a
portion of the particles

are
ionized

(
charged
). Heating a gas
may
ionize

its molecules or atoms
(reduce or increase the number of
electrons

in them), thus turning it
into a plasma, which contains
positive
ions

and negative electrons
or ions.

Ionization can

be
induced

by other means, such as strong
electromagnetic field applied

with
a
laser

or
microwave

generator
, and
is accompanied by the dissociation
of
molecular bonds
.

Neon signs,
lasers,
stars
, most of the uni verse

Critical thinking 3

If
a gas is heated
, at a sufficiently high temperature, the electrons will separate to
form free electrons and positive ions. This
is
plasma
. If some of the electrons
leave the atom then some electrons are left on the atom. Why is the atom missing
some el
ectrons considered a positive ion?

The number of protons is more than the number of electrons

so the atom still has a strong net charge of positive

Wrap
-
up 3

The common
states of matter

on Earth
:
solids, liquids and gases
.

In the
Universe
, the common state of matter is
plasma
. Heat a solid element and it
melts, heat the resulting liquid further and it turns to gas. In all three states, the
atoms of the original solid are still held together by the
electrostatic

attraction
between the nuc
leus and the surrounding electrons. However if this gas is heated
further, at a sufficiently high temperature, the electrons will separate to form free
electrons

and positive
ions
.
This plasma state is common in stars and most of
the rest of the univers
e.

Item Ics 1 Sem1 block 8 EM fields

8.3 Standards

1

5

9

13

17

21

25

29

33

37

5. d.
Students know
the properties of transistors and the role of transistors in electric
circuits.

Semiconductors

are materials with an energy barrier such that only electrons with energy
above a certain amount can “flow.” As the temperature rises, more electrons are free to
move through these materials. A
transistor

is made of a combination of differently
“doped” ma
terials arranged in a special way. Transistors can be used to control large
current output with a small bias voltage. A common role of transistors in electric circuits
is that of amplifiers. In that role transistors have almost entirely replaced vacuum tub
es
that were widely used in early radios, television sets, and computers.

5. e.
Students know
charged particles are sources of electric fields and are subject to
the forces of the electric fields from other charges.

Electrostatic force

represents an inte
raction across space between two charged bodies.
The magnitude of the force is expressed by a relationship similar to that for the
gravitational force between two bodies with mass. For both gravity and electricity, the
force varies inversely as the square
of the distance between the two bodies. For two
charges
q
1
and
q
2
separated by a distance
r,
the relationship is called
Coulomb’s law
,

F
=
kq
1
q
2
/
r
2

where
k
is a constant. Customary
units for charge

are coulombs (C),

which case
k
= 9 × 10
9
Nm
2
/C
2
.

An electric field is a condition produced in space by the presence of charges. A field is
said to exist in a region of space if a force can be measured on a test charge in the region.
Many different and complicated distributions of electric charge can prod
uce the same
simple motion of a test charge and therefore the same simple field; for that reason it is
usually easier to study first the effect of a model field on a test charge and to consider
only later what distribution of other charges might produce th
at field.

5. h.
Students know
changing magnetic fields produce electric fields, thereby
inducing currents in nearby conductors.

http://www.odec.ca/projects/2007/ball7l2/lenzs_law.ht m

The concept of electromagnetic induction is based on the observation that changing
magnetic fields create electric fields, just as changing electric fields are sources of
magnetic fields. In a conducto
r these induced electric fields can drive a current. The
direction of the induced current is always such as to oppose the changing magnetic field
that caused it. This principle is called
Lenz’s law
.

5. i.
Students know
plasmas, the fourth state of matter,

contain ions or free electrons
or both and conduct electricity.

Plasma

is a mixture of positive ions and free electrons that is electrically neutral on the
whole but that can conduct electricity. Plasma can be created by very high temperatures
when
molecules disassociate and their constituent atoms further break up into positively
charged ions and negatively charged electrons. Much of the matter in the universe is in
stars in the form of plasma, a mixture of electrified fragments of atoms. Plasma is
considered a fourth state of matter, as fundamental as solid, liquid, and gas.

Item Ics 1 Sem1 block 8 EM fields

8.3

Standards

39

43

47

51

55

59

61

65

69

73

5. j.*
Students know
electric and magnetic fields contain energy and act as vector
forc
e fields.

Both the electric field
E
and the magnetic field
B
are vector fields; therefore, they have a
magnitude and a direction. The fields from matter whose distributions in space and in
velocity do not change with time are easy to visualize; for ex
ample, charges fixed in space,
steady electric currents in wires, or permanent magnets. Electric fields from matter like this
are generally represented by “lines of force” that
start on positive charges and end on
negative charges but never form closed loo
ps (see Standard 5.m*, which appears later in
this section). In contrast, the lines for magnetic fields always form closed loops; they never
start and end

magnetic field lines do not have terminal points. Even the magnetic field
lines around simple bar mag
nets, which are typically drawn as emanating from the north
pole and entering the south pole, in fact continue through the body of the magnet to form
closed loops.

The reason magnetic fields form loops while electric fields do not has to do with their
dif
ferent sources in matter at rest. Electric fields come from point charges, and magnetic
fields come from point dipoles, which are more complicated; no sources of magnetic field
with the simple properties of charge

that is, no magnetic monopoles

are known t
o exist.
The direction in which an electric field points along a line of force is away from positive
charge and toward negative charge; the direction in which a magnetic field (that is due to a
current) points along a closed loop can be found by the right
-
hand rule (see Standard 5.g,
which appears earlier in this section).

Electric and magnetic fields are associated with the existence of potential energy. The
fields are usually said to
contain
energy. For example, the potential energy of a system of
two ch
arges
q
1
and
q
2
located a distance

r

apart, is given by

PE
=
k

q
1

q
2

/

r

In general, the potential energy of a system of fixed
-
point charges is defined as the
work required to assemble

the system bringing each charge in from an infinite distance.

5. m.*
Students know
static electric fields have as their source some arrangement of
electric charges.

The existence of a static electric field in a region of space implies a distribution of
charges as the source. Conversely, any set of charges or charged surfaces sets up an
electric field in the space around the charge. The customary first step in visualiz
ing an
electric field is to draw smooth curves, each of which contains only points of equal electric
potential. Electric field lines (“lines of force”) can then be drawn as curves that are
everywhere perpendicular to the curves of equal potential. Electric

field lines are assigned
a direction that runs from regions of high potential to low and, therefore, from positive
point charges to negative ones. The lines of force represent the path a particle with a small
positive charge would take if released in the
field.

At each point a net vector
E
is obtained by summing the vector contributions from each
charge. This process can be readily done for a two
-
charge system in which the geometry is
relatively simple. For more complicated distributions the methods

of calculus are generally
required to obtain the field.

Item Ics 1 Sem1 block 8 EM fields

8.3

Standards Q
uestions

1.

How does a temperature rise, help more electrons to move through Semiconductor materials easier?

Temperature increases free electrons move

fast and increase in quantity

2.

Amplification depends on the change in the transistor’s resistance caused by an input signal.

How does resistance influence amplification?

Increases amplification, decrease resistance

3.

Are charged particles sources of

electric field
s
?

yes

4.

Are charged
particles subject to the forces of the electric fields from other charges?

yes

5.

What does the Electrostatic force represent?

F= k q1 q2 / r
2

6.

What relationship is like the
magnitude
of the force?

speed limit, just a value

7.

What does the force inversely
depend upon?

r
2

= distance

8.

What are the three force variables?

q
1 q2 r

9.

What is the relationship called
that gives force as a function of three variables?

Coulombs Law

10.

What does k stand for? Give value.

9 x 10
9

11.

What must be present to create an
electric field?

Charge

12.

A field is said to exist in a region of space if a _______ can be measured on test charge in the region.

charge and or force

13.

Why is it easier to study first the effect of a model field on a test charge and to consider only later w
hat
distribution of other charges might produce that field?

Item Ics 1 Sem1 block 8 EM fields

14.

Do changing magnetic fields produce electric fields?

y
e
s

15.

Can changing magnetic field produce current in a nearby conductor?

yes

16.

In a conductor induced electric fields can drive a current.

The

current flows in the direction of your right
thumb then magnetic field flows in the path of you curling

Fingers

17.

The direction of the induced current is always ___
90
__ the changing (fill in the
rest)______________
magnetic
field
_________________________________.

18.

The
induced current, opposite
the changing magnetic field

is known as

Lenz

law.

19.

Plasmas are known as the

fourth state of matter,
because they are not a solid, liquid, or gas but a
group of atoms that have lost an e
lectron therefore having a
positive charge and

are called
ions

20.

Why can plasma conduct electricity?

has free electrons

21.

Both the electric field
E
and the magnetic field
B
are vector fields; therefore, they have
a _
Magnitude
_
and a direction.

22.

Electric fields from matter are generally represented by “lines of force” that start on
__
+
___

charges and
end on
____
-
____
charges but never form
__
closed
___

loops
.

23.

In contrast,

lines for magnetic fields always form
__
closed
___

loops; they
___
never
___

start and
end

magnetic field lines do not have terminal points.

24.

Electric fields come from point _
Charges
___
while Magnetic Fields come from point

Dipole
__

25.

Electric and magnetic fields are associated with the existence of potential energy. The fields are usually
said to
contain
energy.
T
he potential energy of a system of two charges
q
1
and
q
2
located a distance
r
apart,
using constant k,
is given by

F
=Kq1q2 / r
2

26.

The static Electric field arrives from a distribution of charged particles. Even with many charges involved
the direction of the field lines is still

_____
From
_______ positive charge and ____
To
____ negative charge.

Item Ics 1 Sem1 block 8 EM fields

8.4
Vocabulary

1.

Semiconductors
-

materials with an energy

barrier such that only electrons with energy above a certain
amount can “flow”

2.

Amplification depends on the change in the transistor’s resistance caused by an input signal

3.

Temperature
-

calculation of disorder

4.

Electrons
-

negative charge particle that orbits around the positive nucleus

5.

Effective resistance
-

of the transistor, is measured across the emitter and the collector, it measures “flow
availability”

6.

Transistor
-

is made of a combination of different mate
rials arranged in a special way,

used to control large current output with a small bias voltage.

7.

Amplifier
-
Magnifies or minimizes the frequency of waves

8.

Amplification
-
The ability of a circuit to receive a small change of input voltage or current
(signa
l) and produce a large change in the output voltage or current (signal)

9.

Electrostatic force
-

represents an interaction across space between two charged bodies.

10.

Coulomb’s law
-

Electrical force which varies inversely as the square of the distance

between the two bodies, and For two charges
q
1
and
q
2
separated by a distance.

11.

Coulombs, C
-

units for charge

12.

Lenz’s law
-
The direction of the induced current is always such as to oppose the changing

magnetic field that caused it.

13.

Plasma
-

is a mixture of positive ions and free electrons that is electrically neutral on the

whole but that can conduct electricity.

14.

Switch
-

is a device that can be made to have a very large resistance when “open” and a

very

small resistance when “closed”. Closed means bridge is open for travel

Pg 627

15.

Analog
-

Description of a continuously variable signal or a cicuit; an analog

signal can be represented as a series of waves

16.

Capacitor
-
a component of an electrical circuit us
ed to temporarily store charge

17.

Circuit diagram
-
drawing that uses a special set of symbols to represent

the electrical

components and wiring of a circuit

18.

Circuit
-

a route laid out with wires that connect circuit components along

which

electrical current flows

Item Ics 1 Sem1 block 8 EM fields

19.

Digital
-
description of data that is stored or transmitted as a sequence of symbols, usually binary code
(1’s and 0’s)

Item Ics 1 Sem1 block 8 EM fields

8.5.1

notes Transistors

5. d. Students know the properties of transistors and their role in electric
circuits.

Semiconductors

are materials that only electrons with
certain
energy
can “flow

through.

As the temperature rises, more electrons are
free to move through these materials.

Transistor

1.

Combination of differently
“doped”

materials arranged in a particular
way

impurities

2.

three terminal

device

3.

Can
change its effective resistance

(a more general term would be “
impedance
”) by the
application of an electrical signal.

4.

Used

as switches or amplifiers in electric circuits.

5.

Used to control large current output with a small bias voltage.

6.

R
eplaced the vacuum tube in most modern electronic applications

7.

An integrate
d circuit used in a computer can have

over one mil
lion transistors etched into it

8.

small electric signal to the base can cause a large change in the Effective Resistance

9.

Two

basic types, the
NPN

and the
PNP

10.

A junction NPN, P type semiconductor sandwiched between two pieces of
N type semiconductor. Likewise, a PNP is reverse.

PNP

NPN

Video on pnp and npn transitor types

http://www.youtube.com/watch?v=ZaBLiciesOU

emitter

base

collector

emitter

base

collector

The arrow points in the direction of
conventional current when the diode is
conducting. This means, if the left end is
connected to plus and the
right is
connected to minus, conventional current
will flow in the direction of the arrow.
Many simple circuits have been developed
using diodes that will convert AC to DC.

Item Ics 1 Sem1 block 8 EM fields

8
.5.2

notes Charge and E
-
field

5. e. Students know charged particles are sources of electric fields and experience forces due to the
electric fields from ot
her charges.

C
harge
-

fundamental quantity
(basic level)

Recall about Mass
:

o

All mass has
in
ertia

o

All mass

attract one another

o

Newton’s law of universal gravitation:
“action at a distance”

F = Gm
1
m
2
/r
2
.

Where G is 6.67 x 10
-
11

N m
2
/ kg
2

m’s

are two different masses, r is the distance between
them

Charge

o

All charge has mass therefore inertia

o

Neutral, plus, and minus

o

same

charges repel

each other

o

different
charges attract one another

o

Coulomb’s law:

”space surrounding a charged object
was
actually modified by the charge “

F = kq
1
q
2
/r
2

where k is 9 X 10
9

N

m
2

/

C
2

q,s are two different charges, r is the distance between
them

The parts of the atom:

Neutrons have mass, inertia, no charge
, no direction of field lines

Electrons have

mass
, inertia, negative charge
, inward direction of field lines

Protons have mass, inertia, positive charge
, outward direction of field lines

Ions have mass, inertia, positive charge
, outward direction of field lines

Electrons and protons have the same
size of charge, magnitude of charge,

but vastly different masses

Unit of electric charge:

One

coulomb

= one amp second.

Definition

of current: I = q/t current equals charge per time

One coulomb of charge is the amount of charge that passes by a point in a circuit carrying a current of
one amp in one second.

Introduction to the Electric Field

Field lines in a

space
are modified by
other charge
s

Lines
are

close
together repres
ents

strength of the field

Electric field is from a stationary and moving charge

Magnetic field from a moving charge or difference in charge

Right hand rule: moving charge direction (current) is your thumb and fingers

curled

is the direction of the magnetic field always perpendicular to the current

Video mythbusters van der graff generator

http://www.youtube.com/watch?v=7qgM1A3pgkQ&feature=watch
-
v
rec

Video of van der grafff and electron flow

http://www.youtube.com/watch?NR=1&v=ubZuSZYVBng&feature=endscreen

Item Ics 1 Sem1 block 8 EM fields

8.5.3

notes EM induction

5. h. Changing
magnetic fields produce electric fields, thereby inducing currents in nearby conductors
.

Electr
omagnetic induction
-

with magnet and coil

Bar
magnet

into a
coil
of wire

Attached to a
galvanometer

that
Measures negative of positive polarity.

The
magnet

must be
moving

relative to the coil

First
pole

of magnet in tells the
direction of the current

measured

Electromagnetic induction
-

with an electromagnet

Two coils near one another

Lenz’s Law and back emf

Faraday, Henry and Lenz discovered electromagnetic induction at
ap
proximately the same time, 1880’s

A

change

in magnetic field was required to produce a current in the coil

Lenz understood that the current must be in a direction to
oppose

the
change.
This is r
elate
d

to the conservation of energy principle.

Video of lenz law in pipe

http://www.youtube.com/watch?v=kU6NSh7hr7Q&feature=related

video neodymium in copper pipe

http://www.youtube.com/watch?v=kU6NSh7hr7Q&feature=related

place

a bar of iron through both coils.
However, this will so vastly increase the
effect; use caution when you connect the
battery since you could exceed the limits of
the galvanometer. Show what happens
when you change the polarity of the
battery, the number
of cells, etc. These
demonstrations

should easily lead to the
basics of how a transformer works.

Item Ics 1 Sem1 block 8 EM fields

8.5.4

notes Plasma

5. i. Students know plasmas, the fourth state of matter, contain ions and/or free electrons and conduct electricity.

Common
three states of matter:
solids
, liquids

and gasses

In the
Universe
,
the
most

co
mmon state of matter is
plasma

Heat a solid element and it melts, heat the resulting liquid further and it turns to gas.

A small fraction of the
mercury vapor in a fluorescent light

will be in the plasma state whil
e the light is on.

Property

Plasma

Electrical
conductivity

Usually very high
: For many purposes, the
conductivity

of
plasma

may be
treated as infinite.

Types

Electrons
,

ions
,

protons

and

neutrons

can be distinguished by the sign and value
of their

charge

so that they behave independently in many

circumstances, with
different bulk velocities and temperatures, allowing phenomena such as new
types of

waves

and

instabilities
.

Velocity
distribution

Collisional interactions are often weak in hot plasmas and external forcing can
drive the plasma far from local equilibrium and lead to a significant population
of unusually fast particles.

Interactions

Waves, or organized motion of plasma, are very important because the particles
can interact at long ranges through the electric and magnetic forces.

A plasma TV consists of a huge number of tiny fluorescent lights with coatings designed to produce three

different colors
per pixel and these are individually addressed with the TV signal to produce the desired picture. Although neither the
fluorescent light nor the plasma TV contains many atoms in the plasma state, there are perhaps enough to earn the name

“plasma.”

Video from Maryland unive.

2
:
35 min

http://www.youtube.com/watch?v=VkeSI_B5Ljc&feature=related

Item Ics 1 Sem1 block 8 EM fields

8.6.1 worksheet Transistors

1.

T

Semiconductors are materials that only electrons with certain energy can “flow” through.

2.

F

As the temperature rises,
fewer

electrons are free to move through materials.

3.

F

Combination of differently “doped” materials arranged in a
random

way

4.

F

Four

terminal device

5.

T

Can change its effective resistance

(a more general term would be “impedance”) by the application
of an electrical signal.

6.

F

Transistors are u
sed

only

as
an amplifier
in electric circuits.

7.

F

Transistors are u
sed to control large current
input

with a small bias voltage.

8.

F

Transistors
Replaced the vacuum tube in most
modern
mechanical

applications

9.

T

An integrated circuit used in a computer can have over one million transistors etched into it

10.

T

small electric signal to the
emitter

can cause a large change in the Effective Resistance

11.

F

One

basic type of transistor,

the
NPN
.

12.

F

A junction NPN, P type semiconductor sandwiched between two pieces of N type
. When the
number of holes and electrons is
equal

change will begin to flow.

a)

Transistor

b)

Semiconductors

c)

Temperature rises

d)

Electrons

e)

Amplifiers

f)

Transistors

g)

Current

h)

Vacuum tubes

i)

Voltage

1.

_______
b
_______ are materials with an
energy
barrier.

2.

The energy barrier must be set up so only
_______
d
_______ with energy above a certain
amount can “flow.”

3.

As the _____
C
______, more of the charged particles
are free to move through a certain group of
materials.

4.

A

______
a
_________ is made
of a combination of
differently “doped” materials arranged in a special
way.

5.

The differently “doped” materials arranged in a
special way,
.can

are used to control large
_____
F
_______

output.

6.

The control mechanism for large output is using a
small bias ___
___
i
_________.

7.

A common role of transistors in electric circuits is
that of an ______
e
_______.

8.

In that role transistors have almost entirely replaced
________
H
_________ that were widely used in
early radios, television sets, and computers.

Item Ics 1 Sem1 block 8 EM fields

8.6.2
.1

worksheet Charge and E0field

Static Electricity Lightning

Item Ics 1 Sem1 block 8 EM fields

8.6.2
.1

worksheet Charge and E
-
field

Static Electricity

Types of Lightning

Lightning is one of nature’s spectacular phenomena. It is also

one of the most common. At any
given moment,
about 2000 thunderstorms take place around the world.
In the United States, lightning
strikes hit millions of
points every year.

A

Discharge within cloud from negative center to positive top

B

Typical cloud to ground lightning, negative centers and positive ground

C

Cloud to cloud discharge between negative and positive centers

D

Cloud to cloud intra cloud strike

The most familiar lightning bolts are
cloud
-
to
-
ground lightning
. The bottom of

the cloud is negatively

charged, while the ground is positively charged. Static energy moves from the bottom of the cloud to

the ground in sections called
step
-
leaders
. That’s why the bolts appear jagged. As a step
-
leader gets

close

to the ground, a positively charged bolt called a
leader
flashes up from the ground to meet it. This

is ground
-
to
-
cloud lightning. The most common lightning doesn’t hit the ground. Lightning that goes between sections of a cloud is
called
intracloud light
ning
. It redistributes energy between positive and negative areas in the same cloud. Usually, intracloud lightning
bolts are not visible. Instead

it looks like a broad flash in the sky

and is often called
sheet lightning
. Lightning between oppositely charg
ed areas of different clouds is called
cloud
-
to
-
cloud lightning
.
Lightning can also move from a cloud to a charged

air
pocket. This lightning is called
cloud
-
to
-
air lightning
.

Answer the following questions, using complete sentences.

1.

What are the common
features of all of these forms of lightning?

2.
Why are we usually unaware of ground
-
to
-
cloud lightning?

A

B

C

D

Item Ics 1 Sem1 block 8 EM fields

8.6.2
.2

worksheet
Charge and E
-
field

Static Electricity

crossword

Across

1.
Negatively charged atomic particle

8.
You can get it from touching
uninsulated wire

9.
Positively charged atomic particle

11.
It hold protons and neutrons together in the
nucleus (3 words)

14.
What like charges do

16.
Electrons cannot move through it easily

18.
Tiny particle of matter

19.
Provide a pathway to drain excess

charge

20.
An example of an electric discharge

21.
A good insulator

Down

2.
Metal used for electrical wire

3.
It gets stronger as you get closer to an electric charge (2
words)

4.
Charge of an atom that has gained electrons

5.
State of an atom with the s
ame number of protons and
electrons (2 words)

6.
Electrons move through it easily

7.
What opposite charges do

10.
Charge of an atom that has lost electrons

12.
Type of charge produced when an electric field
separates positive and negative charges

13.
Atomi
c particle that has no charge

15.
Build up of electric charges

17.
A way electrons can be transferred

Item Ics 1 Sem1 block 8 EM fields

8.6
.3.1
worksheet
EM induction

Electric Current

How much electricity do you use?

Jerome and Janet are working on a budget. To plan for the
cost of electricity, they gather information about how much
energy their appliances use in a year.
(
Listed

in the tabl
e)

Then they
looked at a bill from the
electric power
supplier to learn more
about costs. The

electric company
bills people for the amount of electricity they use, based on a
unit called the kilowatt
-
hour. A kilowatt
-
hour equals the
amount of energy produced
by one kilowatt of power in one
hour.

Jerome and Janet need a yearly kilow
att
-
hour / year
dollar amount. Then a monthly dollar amount can be found

for their budget.

Suppose

the electric company
bill
charges \$0
.
13 for a kilowatt
-
hour. Calculate how much each of

these
appliances would cost
Jerome and Janet
per year then per month

Per year (0.13)

Per month (0.13)(1/12)

Per week (0.13)(1/52)

1.
Doing the laundry

2.
Using the microwave oven

3.
Vacuuming the h
ouse

4.
Watching television

5.
Running the dishwasher

6.
On the computer

Appliance

Kilowatt
-
hours
used per year

stated by
manufacturer

Dishwasher

Microwave oven

Toaster

Washing machine

Clothes drier

Vacuum cleaner

Hair dryer

Color television

Computer

363

190

39

103

933

46

14

440

400

Item Ics 1 Sem1 block 8 EM fields

8.6.3
.2 worksheet EM induction

What is magnetism
?

Which way is north?

When you get home from school, your mom tells you she has a surprise for you. When you ask what

it

is, she gets a big smile on her face and says, “To get your surprise, you must solve a problem first.”

She has a golf ball with a small bar magnet inside, and she wants you to find a way to determine

which end of the magnet is the south pole and which end

is the north pole.

1.
Using complete sentences, describe how you would determine the north and south poles of the

magnet. Can you think of more than one way to find them?

Don’t do

by direction of current using the right hand rule

While you are workin
g on your solution, your dad comes home and asks you what you’re doing.

Finally, you share your solution with your mom and dad, and you ask for your surprise. This time

your dad tells you that you must solve another problem before you get your surprise. Us
ing the

golf ball from the earlier problem, you must decide which would be faster; to use another magnet

to pull the golf ball three meters, or to use another magnet to push the golf ball three meters. If you

choose to push the golf ball with the other mag
net, the golf ball and the other magnet cannot touch

each other.

2.
Explain your choice in complete sentences. You may include the properties of magnets that you

learned about in this section.

Don’t do

3.
Obtain two bar magnets from your teacher.
Set them on a hard surface such as a counter top, or a

tiled floor. Using a meter stick, measure three meters. Mark a starting point and an ending point.

Test your answer to Question 2 above. Which way is quicker?

Don’t do

Item Ics 1 Sem1 block 8 EM fields

8.6.3
.3 worksheet EM induction

Magnetic field of

Earth

Earth itself is a huge magnet, and, like any magnet, it has poles.
The places that we call the north and

south poles are not Earth’
s
magnetic poles
however. The north and south poles are the geographic,
or

true, poles, which ar
e in line with the axis that Earth spins around.
The magnetic poles are shifting

points near the true poles. Currently,
the magnetic poles are located several hundred kilometers from

the true
poles.

When you use a compass, the compas
s needle points to the

magnetic poles
. A compass is a magnet

with north and south poles and
is attracted by Earth’s magnetism. For centuries, people have used

compasses for navigation.

Refer to the diagram and use what you have read and what you know about magnets and their p
oles to answer these

questions.

1.
Imagine you are standing at point A. Which way would the north needle of your compass point?

North

2.
The markings on a map that indicate north point to the true north pole. Why does this present a

problem

for making a compass reading at point B?

at B the compass points to the left of true North

3.
What would your compass read if you were standing at point C, the true north pole?

North is Behind or South

Challenge Question

4.
The north pole (north
-
pointi
ng needle) of a compass points to Earth’s north magnetic pole. The

north magnetic pole is actually the south pole of Earth’s magnet. Explain why this must be so,

based on what you know about magnetic attraction.

Item Ics 1 Sem1 block 8 EM fields

8.6.4 worksheet Plasma

Directions
:
Answer the following questions in
complete

sentences. A diagram may be

substituted when
appropriate.

1.

Name at least
five

places where you can find plasmas.

Sun, Nebula Cloud around supernova remnant

Cutting tools, Solar Corona, Lightning, Aurora borealis

Neon signs, Florescent

light, interstellar space, magnetic confinement fusion

2.

What is the key
difference

between plasma and a normal gas?

Gas the Electrons are bonded with atoms, molecules, compounds

Plasma the outer electrons are free of bonding and the Atom is left as a pos
itive
ion
.

3.

Why does plasma have a particular
frequency

associated with it?

Since plasma has both positive and negative charges, they are constantly oscillating back and
forth. This results in a characteristic frequency called the Plasma Frequency

The p
lasma frequency is a resonant frequency of the ionized gas
-

it depends on the square root of
the electron density

4.

What role does atmospheric plasma play in
radio comm
unication
? Ionosphere

Radio waves can only penetrate the ionosphere if the frequency of the wave is higher than the
plasma frequency; otherwise the signal is reflected back

We have to use high frequencies to communicate with satellites.

Frequencies lower t
han the plasma frequency have to be used to communicate with a radio
station beyond the horizon so that the signal will be reflected back to Earth

5.

What effects does
interstellar

plasma have on radio signals?

The solar wind causes energy changes in the incoming wavefront

Plasma Facts

true / false

6.

_
T
__
More than 99 percent of the known matter in the universe is in the plasma state

7.

_
T
__
Plasmas are made up of particles that have broken apart

8.

_
F
__
Plasmas

have a definite shape and volume

9.

_
F
__
Plasmas and gases conduct electric current

10.

__
T
_
Plasmas are affected by magnetic fields

11.

Lightning and fire are examples of
___
Natural
___
plasmas

12.

The incredible light show in

the f
igure, is caused by plasma. How?

High
-
ene
rgy plasma collides with particles in the upper atmosphere,causing them to glow.

Changes of State

13.

When a substance changes from one _
_
Physical
___form to another, we say the substance has had a
change of state.

14.

List the five changes of state.

melting,
freezing, vaporization, condensation, and sublimation

Energy and Changes of State
-

true / false

15.

_
F
__
The identity of a substance changes during a change of state.

16.

_
T
_
_
Temperature is the measure of the speed of particles.

17.

_
F
__
Temperature

is a transfer of energy.

18.

Which has the most energy?

a.

particles in steam

c.
particles in ice

b.

particles in liquid water

d.
particles in freezing water

Item Ics 1 Sem1 block 8 EM fields

8.7 Study guide and CST Prep

5. d.

Use these next five choices to answer the next

four questions

1
-
4

a)

Transistor

b)

Semiconductors

c)

Pressure falls

d)

Temperature rises

e)

Electrons

9.

________
____
____ are materials with an energy barrier.

10.

The energy barrier must be set up so only
______
__________ with energy above a certain amount can
“flow.”

11.

As the
______
_______, more of the charged particles are free to move through a certain group of materials.

12.

A
_____________
___ is made of a combination of differently “doped” materials arranged in

a special way.

Use these next five choices to answer the next four questions

5
-
8

a)

Amplifiers

b)

Transistors

c)

Current

d)

Vacuum tubes

e)

Voltage

13.

The differently “doped” materials arranged in a special way, .can are used to control large
______________output.

14.

The control mechanism for large output is using a small bias _________________.

15.

A common role of transistors in electric circuits is that of an _______________.

16.

In that role transistors have almost entirely replaced ___________________ that were widely
used in early
radios, television sets, and computers.

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _
_ _ _ _

17.

A transistor circuit is used as an amplifier. When a signal is applied to the input of the transistor, the output
signal is

A
a smaller amplitude
B
an equal amplitude
C
a larger amplitude
D
zero amplitude

Item Ics 1 Sem1 block 8 EM fields

8.7 Study guide and CST Prep

5. e.

Use these next five
choices to answer the next two questions.

a)

Gravitational force

b)

M
agnitude
,

gravitational force

c)

Electrostatic force

d)

Charge, electric force

e)

Magnitude

18.

_______
_______ represents an interaction across space between two charged bodies.

19.

The
_______
_____
of the force between two charged bodies is

expressed by a relationship similar
to that for the
___
___
____ between two bodies with mass.

Use these next five choices to answer the next three questions.

a)

Lenz’s Law

G
ravity
,

electricity
,

inversely

c)

Coulomb’s law

Gravity, electricity, linearly

e)

Units for charge

20.

For both
___
_____ and ____
___, the force varies
__
_
__
__ as the square of the distance between
the two bodies.

21.

For two charges
q
1
and
q
2
separated by a distance
r,
the relationship is called
__
___,

F
=
kq
1
q
2
/
r
2
where
k
is a constant.

22.

Customary
________
____ are coulombs (C), in which case
k
= 9 × 10
9
Nm
2
/C
2
.

Use these next five choices to answer the next three questions.

a)

Charge, field

b)

Charge

c)

Field

d)

Test charge , distribution

e)

Electric field, presence of charges

23.

A
(
n
)

_
____ is a condition produced in space by the
_
____.

24.

A
_
_
_
_ is said to exist in a region of space if a force can be measured on a test charge in the region.

25.

Many different and complicated distributions of electric charge can produce the same simple
motion of
a
_____and therefore the same simple field; for that reason it is usually easier to study
first the effect of a model field on a test charge and to consid
er only later what
__
___ of other
charges might produce that field.

Item Ics 1 Sem1 block 8 EM fields

8.7 Study guide and CST Prep

5. e.

26.

Two oppositely charged particles are held in place near each other. When the particles are released, they
will
most
likely

a)

accelerate away from each other

b)

accelerate toward each other

c)

rotate in a clockwise direction

d)

rotate in a counterclockwise direction

Item Ics 1 Sem1 block 8 EM fields

8.7 Study guide and CST Prep

5. h.

Use these next five choices to answer
the next three questions.

a)

Sources

b)

I
nduction

c)

Conduction

d)

Destroy

e)

Create

27.

The concept of electromagnetic ____________________ is based on the observation

28.

The observation in the previous problem is done by understanding that

changing magnetic
fields _______________

electric fields

29.

The opposite to the previous problem is true also
, changing

electric fields are
________________ of magnetic fields.

Use these next five choices to answer the next three questions.

a)

Transistor

b)

Conductor

c)

Induced current

d)

Coulomb’s law

e)

Lenz’s law

30.

In a_____________________ these induced electric fields can drive a current.

31.

The direction of the _________________ is always such as to oppose the changing magnetic
field that caused it.

32.

The

principle

describe in the previous problem

is called __________________.

33.

Students in a lab measure a current flowing through a long loop of wire.

If there is no current source connected to the wire, which of
the following explains the source of the current?

a)

A
mmeter is acting as a current source.

b)

There is an oscillating magnetic field inside the loop.

c)

There is a fixed current running in a separate wire along the axis of the loop.

d)

There is a static configuration of positive charge external to the loop.

34.

In order to turn neon gas into neon plasma,

A
energy must be removed from the neon gas
B
energy must be supplied to the neon gas

C
the neon gas must be

ignited with a flame
D
the neon gas must become a superconductor

Item Ics 1 Sem1 block 8 EM fields

8.7 Study guide and CST Prep

5. i.

Use the next three choices to answer the next question

a)

Plasma

negative

neutral

b)

Plasma

positive

negative

c)

Plasma

positive

neutral

35.

_________________
is a mixture of ________________ ions and free electrons that is electrically
______________on the whole but that can conduct electricity.

Use the next five choices to answer the next three questions

a)

Associate

b)

Fourth state

c)

Disassociate

d)

Inner
Planets

e)

Universe

36.

Plasma

can be created by very high temperatures when molecules _____________________and their
constituent atoms further break up into positively charged ions and negatively charged electrons.

37.

Much of the matter in the
______________

is in stars in the form of plasma, a mixture of electrified
fragments of atoms.

38.

Plasma is considered a ____________________ of matter, as fundamental as solid, liquid, and gas.

_ _ _ _ _ _ _

_ _ _ _ _ _ _

39.

In order to turn neon gas into neon plasma,

a)

energy must be removed from the neon gas

b)

energy must be supplied to the neon gas

c)

the neon gas must be ignited with a flame

d)

the neon

gas must become a superconductor

40.

Extremely high temperatures are needed for fusion reactors to function efficiently.

What state of matter is
most
common at these temperatures?

a)

plasma

b)

gas

c)

liquid

d )

s o l i d

Item Ics 1 Sem1 block 8 EM fields

8.7 Study guide and CST Prep

5. j.*

E

B

vector

magnitude

Both the electric field
____

and the magnetic field
_____

are
_______
fields; therefore, they have a
________________ and a ______________
.

direction

do not change

from matter

start

positive charges end negative
charges closed loops terminal points

from north pole entering south pole

different sources in matter point charges

point dipoles no magnetic monopoles

away

positive charge

toward negative charge

right
-
hand rule potential energy work

The fields from matter whose distributions in space and in velocity

___________________

with time are
easy to visualize; for example, charges fixed in space, steady electric currents in wires, or permanent magnets.

Electric fields
_______________

like this are generally represented by “lines of force” that
___________
on
___________________ and _________ on _____________________

but never form closed loops
.

In contrast, the lines for magnetic fields always form
________________
; they never start and end

magnetic
field lines do not have
____________________
.

Even the

magnetic field lines around simple bar magnets, which are typically drawn as emanating
______________ the ________________ and ______________ the _______________
, in fact continue
through the body of the magnet to form closed loops.

The reason magnetic fields form loops while electric fields do not has to do with their
_____________________

at rest.

Electric fields come from
______________________
, and magnetic fields come from
______________________
, which are more complicated; no
sources of magnetic field with the simple
properties of charge

that is,
__________________________ a
re known to exist.

The direction in which an electric field points along a line of force is
___________________ from
__________________ and ______________
__________
; the direction in which a magnetic field (that is due to
a current) points along a closed loop can be found by the
________________________

(see Standard 5.g,
which appears earlier in this section).

Electric and magnetic fields are associated
with the existence of
_________________________
. The fields
are usually said to
contain
energy.

For example, the potential energy of a system of two charges
q
1
and
q
2
located a distance

r

apart, is given
by

PE
=
k

q
1

q
2

/

r

In general, the potential energy of a system of fixed
-
point charges is defined as the
____________________

required to assemble the system bringing each charge in from an infinite distance.

Item Ics 1 Sem1 block 8 EM fields

8.7 Study guide and CST Prep

5. m.*

static

any set smooth curves

electric potential

perpendicular high low
to

path positive net summing geometry calculus

The existence of a
_________

electric field in a region o
f space implies a distribution of charges as the
source.

Conversely,
___________

of charges or charged surfaces sets up an electric field in the space around
the charge.

The customary first step in visualizing an electric field is to draw
_____________
_
, each of which
contains only points of equal
__________________
.

Electric field lines (“lines of force”) can then be drawn as curves that are everywhere
___________________
to the curves of equal potential.

Electric field lines are assigned a directio
n that runs from regions of
___________
potential to
___________

and, therefore, from positive point charges
__________

negative ones.

The lines of force represent the
____________

a particle with a small
______________

charge would
take if released in the field.

At each point a
_____________
vector
E
is obtained by
_____________

the vector contributions from
each charge.

This process can be readily done for a two
-
charge system in which the
______________

is rela
tively
simple.

For more complicated distributions the methods of
______________

are generally required to obtain the
field.