Presentation on theme: "Final Problem EQ6: Is Light a wave?. Light is a form of radiation. It is the transfer of energy from place to place without the need of a medium. For."— Presentation transcript:
Light is a form of radiation. It is the transfer of energy from place to place without the need of a medium. For example, light travels from the Sun to the Earth, about 93,000,000 miles, through empty space before it reaches our thin atmosphere and then us. But is light a wave?
Yes and no. Light is an invisible bundle of energy with a specific wavelength that is given off by excited electrons. Absorption / emission of photon Emission of photons
Photon Absorption and Emission Electrons will absorb an incident photon that allows it to jump one or more energy levels, then it falls back and gives off a specific energy photon.
Excited electrons vibrate as they jump levels and then fall back. This movement of charge creates electric and magnetic fields and thus gives off electromagnetic (EM) photons / waves. The wavelength of the photons depends on the energy of the energy level drop. High energy photons mean short wavelengths or high frequency.
All EM waves have same very high speed in a vacuum, 300,000 km/s, or 186,000 miles/s (7 times around Earth/s) Speed of light symbol is “c” c is max. universe speed
Light is a wave that carries energy outward from a source of EM vibration (vibrating electrons) Light is a transverse wave that has a λ of 400-700 nm (nano= 1 billionth), in the middle of the em spectrum Retina cells respond to visible light, but not other em radiation Light reflects, refracts, and interferes
If light photons makes electrons resonate, light energy will absorb and be transmitted (transparent) If photons do not make electrons resonate, light energy will reflect back (opaque) If light energy makes some electrons resonate but not all, some light energy will be transmitted (translucent)
Light can be separated into its different wavelengths since short wavelengths of light will bend more than long ones.
Here are some examples of light emitted from various heated elements These lines are called emission lines and the set of lines is an emission line spectrum. Each line is the photon given off by a specific electron fall.
Colors are the signature emitted photons of specific elements!
Hopefully we have shed some light on the subject by illuminating some points to make you brighter so you can really shine.