Transcript 08_light

Light
The EKG showed that
A) Sound is another form of electricity
B) Your body has currents moving through it
C) We emit strong magnetic fields
D) The device charges up your body
periodically
The speaker/microphone helped us to see that:
A) Electrical currents can be produced from a
moving magnet
B) Sound is really a form of electricity
C) There is no magnetism involved in the
conversion from sound to electrical current
D) Sound waves can only be emitted from
electrical activity, not the other way around
Light travels VERY FAST – around
300,000 kilometres (186282 miles) per
second.
At this speed it can
go around the world 8
times in one second.
HIGH energy
LOW energy
The Full Electromagnetic
Spectrum
• Visible, Infrared and UV radiation are only part of
the full spectrum of electromagnetic radiation
Source: http://www.mhhe.com/physsci/astronomy/arny/instructor/graphics/ch03/0305.html
The Sun’s Radiation Spectrum
Most of the sun’s radiation is UV, Vis & IR :
• ~ 43% is in the
visible range
• ~ 49% is in the
near infrared range
• ~ 7% is in the
.
ultraviolet range
• < 1% is x-rays,
gamma waves, and
radio waves
Source: Adapted from http://www.ucar.edu/learn/imgcat.htm
Sunset
By passing white light through a prism,
you can tellA that white light is actually a mixture of
different colors
B the mass of the prism
C the original source of the light
D that blue light is brighter than white
light
Pick up nov 4
Did you vote?
A) Yes!
B) No…
C) I am not able to vote
Do you think that your vote
“counts?”
A)
B)
C)
D)
Yes, definitely
Only indirectly
Only if it is a close call
No
November exam
Exam this month – push back a week?
A) 10-Nov is ok
B) Prefer 17-Nov
C) No exam at all is preferable
Final: Wed Dec 15, 4:30-7pm (I think this room)
Do you want to go over the “nuclear” exam
in Thursday discussion session?
A) Yes
B) No
C) Indifferent
What about for the circuits hw?
A) Yes
B) No
C) Indifferent
Bees see in UV
Additive Colors
• Red, Green, and Blue
light sources can be
used to synthesize
almost any
perceivable color
• Red + Green = Yellow
• Red + Blue =
Magenta
• Green + Blue = Cyan
• These three dualsource colors become
the primary colors for
Pick up Nov 9
Term project – to be worth more?
Do you find it fair to change the grading
scheme for this course based on a class
vote?
A) Yes, if >50% is ok with it.
B) Yes, but only if >67% is ok with it.
C) Not really, but I’ll go along with it.
D) No way!
Term project – to be worth more?
There are multiple ways
to slice it –
A) Midterms=13%,final
=20%, term=18%
B) Midterms=13%,term
=15%
C) Midterms same, final
20%, term 14%
D) Keep the current
scheme
3 midterm exams, 14%
each:
42%
Final exam:
22%
homeworks:
12%
term project:
12%
discussion activities:
7%
clickers:
5%
TOTAL:
100
%
Democracy!
Are you ok with what “we” just decided?
A) Yes
B) No
Invisibility cloak?
One-way mirrors
How do they work?
A) Special engineered one-way material
B) Bright reflected rays on one side
C) Interference of light rays
D) Refraction of light rays
Part 2 - Reflection
Reflection from a mirror:
Normal
Reflected ray
Incident ray
Angle of
incidence
Angle of
reflection
Mirror
A “light-pipe” works by
A) Diffraction
B) Interference
C) Refraction
D) Dispersion
Seeing colour
• The colour an object appears depends on the
colours of light it reflects.
For example, a red book only reflects red light:
White
light
Only red light
is reflected
pick up Nov 11
Polarization
LCD
Kindle…
What’s the wavelength of your i>clicker?
A. 1 nm
B. 200 nm
C. 650 nm
D. 10 micron
E. 30 cm
What’s the wavelength of an x-ray?
A. 1 nm
B. 200 nm
C. 650 nm
D. 10 micron
E. 30 cm
HIGH energy
LOW energy
What’s the peak wavelength of a light bulb
(about 3000 K)?
A) 10 nm
B) 500 nm
C) 1 micron
D) 10 micron
E) 90 micron
Light bulb = 2500 K
What about you? What peak wavelength do
you emit?
A) 10 nm
B) 500 nm
C) 1 micron
D) 10 micron
E) 90 micron
Pick up nov 18
November 2010
Sun
Mon
Tue
Wed
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Sat
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We are
here!
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No
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class
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this
30
CC/Energy
week
December 2010
Sun
Mon
Tue
Wed
Thu
1
Fri
2
6
7
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Quantum
12
13
3
4
Term
project due
Quantum
5
Sat
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Review
14
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Final
4:30-7
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X-rays are particularly sensitive to uranium
and plutonium. Why?
A) They’re radioactive
B) They’re dense
C) They have many electrons
D) They are explosive
Xray backscatter…
CT scans
What does the “M” in MRI mean?
A)
B)
C)
D)
E)
Metallic
Magnetic
Mysterious
Mapping
Microscopic
MRI
PET (positron emission
tomography)
THz (T-rays)
The depletion of the ozone layer
has to do with:
A)
B)
C)
D)
E)
Infrared light
Visible light
UV light
microwaves
Gamma rays
Ozone is the major reason we are worried
about global warming.
A) True
B) False
C) Not sure
Ozone depleting
substances
Developed countries
Developing countries
Chlorofluorocarbons (CFCs)
Phased out end of 1995a
Total phase out by 2010
Halons
Phased out end of 1993
Total phase out by 2010
Carbon tetrachloride
Phased out end of 1995a
Total phase out by 2010
Methyl chloroform
Phased out end of 1995a
Total phase out by 2015
Hydrochlorofluorocarbons
(HCFCs)
Freeze from beginning of
1996b
35% reduction by 2004
75% reduction by 2010
90% reduction by 2015
Total phase out by
2020c
Freeze in 2013 at a base level
calculated as
the average of 2009 and 2010
consumption levels
10% reduction by 2015
35% reduction by 2020
67.5% reduction by 2025
Total phase out by 2030d
Hydrobromofluorocarbons
(HBFCs)
Phased out end of 1995
Phased out end of 1995
Methyl bromide
(horticultural uses)
Freeze in 1995 at 1991
base levele
25% reduction by 1999
50% reduction by 2001
70% reduction by 2003
Total phase out by
2005
Freeze in 2002 at average 1995-1998
base levele
20% reduction by 2005
Total phase out by 2015
Bromochloromethane (BCM)
Phase out by 2002
Phase out by 2002
Review…
Chapter 6: Electricity and Magnetism
Objectives:
Learn the vocabulary and units associated with electricity
Understand how electricity flows around a circuit
Understand the transportation of electricity from a power plant to your home.
Learn how electricity and magnetism are interconnected through the example of a transformer.
Electricity and the Flowing Water Analogy:
Compare this...
to this
Symbol Units
Charge (Amount
of electrons)
I
Rate of flow
Narrowing of
pipe, obstacles to
flow
Pump
Battery
Voltage
Power
Resistance in a wire depends on:
1)
2)
3)
Chapter 6: Electricity and Magnetism
Objectives:
Learn the vocabulary and units associated with electricity
Understand how electricity flows around a circuit
Understand the transportation of electricity from a power plant to your home.
Learn how electricity and magnetism are interconnected through the example of a transformer.
Electricity and the Flowing Water Analogy:
Compare this...
to this
Water
Charge (Amount q
of electrons)
Coulombs
Rate of flow
Current
I
Amps
R
Ohms
Narrowing of
Resistance
pipe, obstacles to
flow
Resistance in a wire depends on:
Symbol Units
Pump
Battery
Water pressure
Voltage
V
Volts
Pumping rate
Power
P
Watts
1) material
2) temperature
3) thickness
1) Power Plants
A
D
B
C
A) Steam, coal, turbine, magnet
B) Magnet, turbine, coal, steam
C) Coal, turbine, magnet, steam
D) Coal, steam, turbine, magnet
1) Power Plants
A) higher
B) lower
High Voltage power lines:
Using the equation P = IV, we see that high
voltage means___________ current.
The goal is to reduce the amount of
_________ lost to___________.
The current leaving a power plant is
____________.
A) Steam, coal, turbine, magnet
B) Magnet, turbine, coal, steam
C) Coal, turbine, magnet, steam
D) Coal, steam, turbine, magnet
1) Power Plants
High Voltage power lines:
Using the equation P = IV, we see that high
voltage means___________ current.
The goal is to reduce the amount of
_________ lost to___________.
The current leaving a power plant is
____________.
A) Steam, coal, turbine, magnet
B) Magnet, turbine, coal, steam
C) Coal, turbine, magnet, steam
D) Coal, steam, turbine, magnet
A)
B)
C)
D)
E)
current / power
energy / heat
voltage / current
steam / heat
heat / power
1) Power Plants
High Voltage power lines:
Using the equation P = IV, we see that high
voltage means___________ current.
The goal is to reduce the amount of
_________ lost to___________.
The current leaving a power plant is
____________.
A) Steam, coal, turbine, magnet
B) Magnet, turbine, coal, steam
C) Coal, turbine, magnet, steam
D) Coal, steam, turbine, magnet
A) AC
B) DC
C) what?
1) Power Plants
Coal, nuclear,
natural gas,
solar
Turbine spins
a wire through
a magnetic
field =
generator
Water is
heated to
produce
steam
High Voltage power lines:
Using the equation P = IV, we see that high
voltage means___________ current.
The goal is to reduce the amount of
_________ lost to___________.
Steam or
hydro turns a
turbine
A) Steam, coal, turbine, magnet
B) Magnet, turbine, coal, steam
C) Coal, turbine, magnet, steam
D) Coal, steam, turbine, magnet
The current leaving a power plant is
____________.
1) Power Plants
Coal, nuclear,
natural gas,
solar
Turbine spins
a wire through
a magnetic
field =
generator
Water is
heated to
produce
steam
High Voltage power lines:
Using the equation P = IV, we see that high
voltage means lower current.
The goal is to reduce the amount of
_________ lost to___________.
Steam or
hydro turns a
turbine
A) Steam, coal, turbine, magnet
B) Magnet, turbine, coal, steam
C) Coal, turbine, magnet, steam
D) Coal, steam, turbine, magnet
The current leaving a power plant is
____________.
1) Power Plants
Coal, nuclear,
natural gas,
solar
Turbine spins
a wire through
a magnetic
field =
generator
Water is
heated to
produce
steam
High Voltage power lines:
Using the equation P = IV, we see that high
voltage means lower current.
The goal is to reduce the amount of energy
lost to heat.
Steam or
hydro turns a
turbine
A) Steam, coal, turbine, magnet
B) Magnet, turbine, coal, steam
C) Coal, turbine, magnet, steam
D) Coal, steam, turbine, magnet
The current leaving a power plant is
____________.
1) Power Plants
Coal, nuclear,
natural gas,
solar
Turbine spins
a wire through
a magnetic
field =
generator
Water is
heated to
produce
steam
High Voltage power lines:
Using the equation P = IV, we see that high
voltage means lower current.
The goal is to reduce the amount of energy
lost to heat.
Steam or
hydro turns a
turbine
A) Steam, coal, turbine, magnet
B) Magnet, turbine, coal, steam
C) Coal, turbine, magnet, steam
D) Coal, steam, turbine, magnet
The current leaving a power plant is AC –
alternating current.
2) Transformers:
induces
induces
Voltage is________
Current is________
Voltage is_______
Current is_______
3) Electricity in the home:
Incoming voltage (U.S.) :
Maximum current:
Frequency:
Fuse box ________.
Wires made of:
Circuit breaker
__________.
2) Transformers:
Changing (AC)
primary current
induces
Changing
magnetic field in induces
the core
Changing
current in the
secondary coil
Voltage is low
Current is high
Voltage is high
Current is low
3) Electricity in the home:
Incoming voltage (U.S.) :
110 V
Maximum current: 15 amps
Frequency: 60 Hz
Fuse box melts.
Wires made of: copper
Circuit breaker resets.
1) Power Plants
A) higher
B) lower
High Voltage power lines:
Using the equation P = IV, we see that high
voltage means___________ current.
The goal is to reduce the amount of
_________ lost to___________.
The current leaving a power plant is
____________.
Interference
How to make a hologram