EM WAVES Flashcards
He had proved that light was an electromagnetic wave
James Clerk Maxwell
In _____ Maxwell wrote down an equation to describe these electromagnetic waves
1865
He noticed that electrical fields and magnetic fields can couple together to form electromagnetic waves
James Clerk Maxwell
He demonstrated the generation and detection of radio waves in 1887, eight years after Maxwell’s death.
Heinrich Hertz
He also showed that these waves travel at the speed of light (as predicted by Maxwell).
Heinrich Hertz
Types of Electromagnetic Radiation (lowest to highest EM spectrum)
RADIOWAVES > MICROWAVES > INFRARED RADIATION > VISIBLE LIGHT > ULTRAVIOLET > XRAYS > GAMMA RAYS
The terms ____, _______ and ______ all refer to the same physical phenomenon: Electromagnetic energy
Light, electromagnetic waves and radiation
The terms light, electromagnetic waves and radiation, all refer to the same physical phenomenon: ?
Electromagnetic energy
the no. of crests that pass a given point within 1 second. Measured in Hertz (Hz); radio waves and microwaves
Frequency
the distance between the crests. Measured in wavelength (meters); infrared rays and visible light
Wavelength
Measured in electron Volts (eV). An electron volt is the amount of kinetic energy needed to move an electron through one-volt potential ; x-rays and gamma rays
Energy
Properties of Electromagnetic Wave
- Transverse wave
- Light is an Electromagnetic wave
- Can travel through a vacuum
- Electromagnetic waves carry energy and momentum
- . They obey the equation c = fλ
What is f and λ
f is frequency in Hertz and λ is wavelength meters
Are at the lowest range of the EM spectrum.
Radio Waves
used primarily for communications including voice, data, and entertainment media.
Radio
fall in the range of the EM spectrum between radio and IR.
Microwaves
used for high-bandwidth communications, radar, and as a heat source for microwave ovens and industrial applications
Microwaves
in the range of the EM spectrum between microwaves and visible light.
Infrared
Is invisible to human eyes, but we can feel it as heat if the intensity is sufficient.
Commonly used as heat sensors
IR Light
is found in the middle of the EM spectrum, between IR and UV.
defined as the wavelengths that are visible to most human eyes..
Visible Light
is a component of sunlight; however, it is invisible to the human eye. It has numerous medical and industrial applications, but it can damage living tissue.
Ultraviolet / UV Light
comprise the range of the EM spectrum between UV and gamma rays
Soft X-rays
occupy the same region of the EM spectrum as gamma rays.
Hard x-rays
X-rays are produced by?
Accelerating electrons
gamma rays are produced by ?
Atomic nuclei
Causes damage to living tissue, which makes it useful for killing cancer cells when applied in carefully measured doses to small regions. Uncontrolled exposure, though, is extremely dangerous to humans
Gamma rays
a measure of the bending of a ray of light when passing from one medium into another
Index of Refraction
a branch of physics that deals with the determination of behavior and the properties of light, along with its interactions with matter and also with the instruments which are used to detect it.
Optics
Defined as the bouncing back of light
Reflection
If the surface is smooth and shiny, like glass, water, or polished metal the light will reflect at the same angle as it hit the surface. This is called ?
Specular Reflection
states that when a ray of light reflects off a surface, the angle of incidence is equal to the
angle of reflection.
Law of Reflection
The image formed by the plane mirror is always _____, _____ and ____ as the object is reflecting,
virtual, upright and same shape and size
It states that incident ray, the refracted ray and the normal to the interface, all lie in the same plane.
Law of Refraction or Snell’s Law
is the bending of light (it also happens with sound, water, and other waves) as it passes from one transparent substance into another.
Refraction
When light travels from air into water, it ______, causing it to change direction slightly
slows down
If light travels go through a substance with a lower refractive index (such as from water into the air) it_______. The light bends AWAY from the normal line.
speeds up
When light enters a denser substance (higher refractive index), it ‘bends’ more _______ the normal line.
TOWARDS
