G10 The Electromagnetic Spectrum Flashcards
postulated that light “coming from the eye” travels in a straight line. He also worked on the reflection of light.
Euclid of Alexandria
famous for his geocentric model of the universe, studied the refraction of light and color phenomena, (c. 100 CE – c. 170 CE)
Claudius Ptolemy
used the apparent change in the position of stars as Earth revolves around the Sun to measure the speed of light
James Bradley
The value he obtained was _ which is within 1% of the current estimate.
(James Bradley)
3.0 x10^8m/s
There were earlier attempts in measuring the speed of light by other scientists, including _ and _ but their methods did not yield any useful results.
Galileo Galilei and Ole Roemer
The current value is at _, which can still be approximated as 3.0 x 108 m/s .
299 910 000 m/s
states that the light is made of a stream of particles travelling in a straight path
particle model
The particle model, states that the light is made of a stream of particles travelling in a straight path. One of the leading proponents of this model is
Isaac Newton
explained as the bouncing of light on a surface, much like a bouncing ball.
Reflection
is explained by the presence of certain force at the interface of two media.
Refraction
states that light is an energy-carrying disturbance or vibration similar to sound and water ripples
wave model
worked on the mathematical theory of the wave nature of light
Christiaan Huygens
is explained as the bouncing of light waves on materials it cannot pass through similar to the echo of sound and ocean waves bouncing on a steep cliff
Reflection
is the slowing down of the waves as light moves to a different medium
Refraction
This also implies that light is capable of interference, or waves amplifying or cancelling each other.
wave model
The current consensus is that electromagnetic waves are _ and _.
both wave and particle
The _ _ is useful in developing radio wave transmission for telecommunications
wave model
_ is useful in developing photovoltaic cells for generation of electricity
particle model
came up with the theory of electromagnetic wave, electric and magnetic fields that induce one another as they propagate. As an electromagnetic wave, it is believed to be capable of travelling through vacuum. - hypothesized that light is an electromagnetic wave because the speed of electromagnetic wave matched the known speed of light.
James Clerk Maxwell
german physicist,using Maxwell’s theories, discovered radio waves by building devices that can produce and receive them. He determined that radio waves also travel at 3.0 x 10^8 m/s, and exhibit wave properties similar to that of light.
He used two rods the serves as the receiver and a spark gap as the receiving antony(antenna) where waves were picked up
Heinrich Hertz
discovery of electromagnetic induction
responsible for introducing the concept of field in physics to describe electromagnetic interaction
made fundamental contributions to the electromagnetic theory of light
Michael Faraday
discovered that a wire carrying electric current can attract or repel another wire next to it that’s also carrying electric current
Ampere’s Law of Electromagnetism
André-Marie Ampère
Electric current in a wire can deflect a magnetized compass needle
Hans Christian Oersted
According to _, since light travels in a straight line, it must be a particle
because waves are known to bend through obstacles. For example, sounds can be
heard through walls since sound waves bend around them
Newton
After various scientists showed the possibility of the particle model of light, _ _ offered an explanation in 1905. He suggested that light, at least in some
instances, should be considered to be composed of small packets of energy or
particles called photons . He added that the energy of each particle was
proportional to the frequency of the electromagnetic radiation that it was a part of
Albert Einstein
ELECTROMAGNETIC WAVE
PROPERTIES
- They are produced by accelerated or
oscillating charge. - They do not require any material or
medium for propagation. - They travel in free space at the
speed of 3x10° m/s
PRINCIPLES
Many natural phenomena exhibit wave-like behaviors. All of
them — water waves, earthquake waves, and sound waves
require a medium to propagate. These are examples of
mechanical waves.
Light can also be described as a wave — a wave of changing
electric and magnetic fields that propagate outward from
their sources. These waves, however, do not require a
medium to propagate.
They propagate at 300,000,000 meters per second through
a vacuum
Electromagnetic waves are transverse waves. In simpler
terms, the changing electric and magnetic fields oscillate
perpendicular to each other and to the direction of the
propagating waves. These changing electric and magnetic
fields generate each other through Faraday’s Law of
Induction and Ampere’s Law of Electromagnetism. These
changing fields dissociate from the oscillating charge and
propagate out into space at the speed of light.
When the oscillating charge accelerates, the moving
charge’s electric fields change, too.
is the passing of light through a material medium
Transmission
Transparent and translucent materials transmit light, but _ materials do not.
opaque
If light is not
transmitted, it may have been _ or _.
reflected or absorbed
the separation of light into different colors. This may happen to a
refracting light depending on the angle from which it entered a new medium and
the nature of this medium.
White light is dispersed into a band of colors: red,
orange, yellow, green, blue, indigo and violet
Dispersion
happens when a material takes in light and converts it into different
forms of energy.
Absorption
_ _ are those that selectively absorb colors. Most
_ _ around us convert light to heat but some materials, such as
leaves and photovoltaic cells, convert some of the light to other forms of energy
such as chemical energy stored as glucose and electrical energy, respectively.
Opaque materials
The leaf absorbs all the frequencies of light except for _ and that _ color is reflected and perceived by the observer’s eyes.
green
When an object appears _, it means it reflects all components of light
white
when an object appears _, it means it absorbs all the components
black
the splitting and bending of light into several random directions. For a
transparent material, _ is due to impurities present in the material. For an
opaque material, light may - in different directions as it bounces off due to
irregularities in the material’s shape
Scattering
Shorter wavelengths of visible light (i.e., blue
and violet) are scattered by nitrogen and oxygen molecules in the atmosphere,
making the sky appear blue. During sunset, the light coming from the sun hits the
atmosphere at a different angle making the sky appear red.
-5-
is the spreading-out of light after passing through a narrow slit. When
the opening is smaller, the _ is greater. The _ is also greater if the
wavelength is longer.
Diffraction
is the overlapping of two or more waves into one wave whenever they pass through the same point
Interference
happens when the opposite parts of two waves meet
Destructive interference
happens when identical parts of two waves meet
Constructive interference
_ _’s double-slit experiment demonstrated that light exhibits interference.
Thomas Young
The _ _ are the areas where waves interfere constructively
bright fringes
_ _ are the areas where waves interfere destructively.
dark fringes
electromagetic spectrum arranged in increasing frequency
radio waves microwaves infrared visible light ultraviolet x-rays gamma rays
speed of electromagnetic waves denoted as
c
Electromagnetic waves travel slower in
denser materials or materials with molecules closer to one another. Thus
light is
faster in air than in water, and faster in water than in glass. It travels fastest in
vacuum where not even a single molecule can be found.
are
transverse waves made of perpendicular electrical and magnetic field components
Electromagnetic waves
refers to the time it takes for the wave to finish one complete wavelength to pass through a point
wave’s period (T)
is the number of complete waves passing through a point in a unit of time
frequency (f)
f=?
1/T
refers to the distance the wave covers per cycle of propagation
can be visualized as one “complete” wave in a series of identical waves
wavelength ( λ )
distance divided by time
Speed
speed of the wave or v=?
v=λ/T
speed using wavelength and frequency
v=λf
electric field and magnetic field of an electromagnetic wave are
_ to each other
perpendicular
frequency is inversely related to the _ of a wave
period
light traveling in a vacuum or empty space
formula
c=λf
greater than 1 meter(an electromagnetic wave)
radio waves
(1 x 10^-3) to (1)
microwaves
(7 x 10^-7) to (1 x 10^-3)
infrared
(4 x 10^-7) x (7 x 10^-7)
visible light
(1 x 10^-8) to (4x10^-7)
ultraviolet
(1 x 10^-10) to (1 x 10^-8)
x-rays
less than 1 x 10^-10 or 100 pm
gamma rays
(6.2 x 10^-7) to (7 x 10^-7)
red
(5.8 x 10^-7) to (6.2 x 10^-7)
orange
(5.3 x 10^-7) to (5.8 x 10^-7)
yellow
(4.7 x 10^-7) to (5.3 x 10^-7)
green
(4.2 x 10^-7) to (4.7 x 10^-7)
blue
(4 x 10^-7) to (4.2 x 10^-7)
violet
electromagnetic waves with the longest wavelength and lowest frequency
radio waves
wavelength just above one meter, and frequencies
below _
(radio waves)
3.0 × 10^8 Hz
wavelengths approximately between one m and one mm.
Microwaves
Their frequencies range from
_ to _ in a vacuum.
(microwave
3.0 × 10^8 to 3.0 × 10^11 Hz
Waves having shorter wavelengths than
microwaves but longer than visible light are called
infrared
occupy the
wavelength roughly between 1 mm and 700 nm
infrared
(nm means nanometer, equivalent
to _ m)
10 ^ -9
mm is _
10^ -3m
infra means
below
visible have wavelengths ranging from _ to _
700 nm
to 400 nm
Arranged in decreasing wavelengths, the order of visible light is
red, orange, yellow,
green, blue, and violet.
under certain conditions, humans may be capable
of seeing infrared at up to _ nm and ultraviolet up to _ nm
1050, 310
ultra means
going beyond
usually from _ nm to _ nm
ultra violet
400, 10
electromagnetic waves with the highest amount of energy
They can pass through several opaque materials such as
human body tissues
X-rays and gamma rays
pm=
10^-12
X-rays with wavelengths from
10 nm to 100 pm
X-rays with wavelengths from
10 nm to 100 pm
are those with wavelengths
less than _ pm
gamma rays
100
Raging Martians Invaded Venus Using
X-ray Guns
