## Presentation on theme: "Radiant Energy  ."— Presentation transcript:

particles or waves of energy emitted
Radiation Electromagnetic radiation – energy released from all objects Nuclear radiation – energy released when a nucleus of an atom changes

Energy emitted from all atoms when electrons move to different energy levels in an atom Energy is not matter it is a wave

Ionizing high energy radiation that produces ions (alpha, beta, gamma) Non-ionizing radiation low energy radiation that doesn’t produce ions

Visible Spectrum

Waves can be described in terms of four characteristics Amplitude Wavelength Frequency speed

Wavelength is distance between crests: 
measured in m, cm, mm, m, nm, etc. Amplitude is the height of wave: Intensity of light depends on amplitude measured in m, cm, mm, m, nm, etc. Frequency is how fast the wave oscillates up and down:  measured in cycles/sec. Also called a Hertz (Hz): 1/sec or sec-1 Speed is the speed of light: 3.00 X 108 m/s c

Calculate Green light has a wavelength of 570 nm. What is it’s frequency? What is the color of light that has a frequency of 4.7 x /sec? (look in book for color)

Energy, frequency and wavelength are related
E= h h= Planck’s constant X 10-34Js

Calculate A certain violet light has a wavelength of 413nm. What is the frequency of the light? What is the energy of the light? = c/ = c/ Convert nm to m  = 3.00X 108m/s = X /s 413 X 10-9m E= h E=( X Js)(7.26 X 10141/s) = 4.81 X 10-19J

Light Is a form of electromagnetic radiation Has dual properties
Behaves like a wave. Moves through space in waves Behaves like a stream of particles called photons Light is quantized – has a specific energy

Wave nature of light Oscillating electromagnetic fields

Nuclear binding energy
E=mc2 Mass is converted to energy Mass proton= amu Mass of neutron= amu 1J=1 kg m2/sec2 1 amu=1.66 x kg