Download what is energy?

WHAT IS ENERGY?
• ABILITY TO DO WORK
• MEASURED IN JOULES (J)
• WORK: TO USE A FORCE TO MOVE AN
OBJECT A DISTANCE
• FXd
WHAT ARE THE TYPES
OF ENERGY?
• KINETIC: ENERGY DUE TO MOTION
• POTENTIAL: ENERGY DUE TO
POSITION
• IDENTIFY THE FOLLOWING:
• CAR ROLLING DOWN A HILL
• STRETCHED RUBBERBAND
WHAT ARE THE
DIFFERENT FORMS
OF ENERGY?
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HEAT (THERMAL)
ELECTROMAGNETIC
CHEMICAL
NUCLEAR
MECHANICAL
SOUND
LIGHT (RADIANT)
THE DUALITY OF LIGHT
• LIGHT IS A VIBRATION
(WAVE) IN ELECTRIC AND
MAGNETIC FIELDS THAT
CAN TRAVEL ACROSS
SPACE AS A PHOTON
(PACKET OF ENERGY).
• IT IS PART OF THE
ELECTROMAGNETIC
SPECTRUM.
• LIGHT CAN BE
REFLECTED, REFRACTED
AND DIFFRACTED
WAVE PROPERTIES
• WAVELENGTH (λ): DISTANCE BETWEEN TWO
IDENTICAL POINTS ON A WAVE (METERS, m)
• FREQUENCY (ƒ): NUMBER OF WAVES THAT PASS A
FIXED POINT IN A SECOND (HERTZ, Hz)
• SPEED OF LIGHT:
c = ƒλ
(3.00 X 108 m/s)
PARTICLE PROPERTIES
• LIGHT TRAVELS IN PHOTONS
(PACKETS OF ENERGY) AND
CAN BE ABSORBED BY
ATOMS.
• PHOTOELECTRIC EFFECT:
EJECTION OF ELECTRONS
FROM THE SURFACE OF A
METAL OR OTHER
MATERIAL WHEN LIGHT
SHINES ON IT (EINSTEIN)
• E =hƒ
• ENERGY = PLANCK’S
CONSTANT (6.63 X 1034 J/s) X
FREQUENCY
HOW CAN A LINE
SPECTRA IDENTIFY
AN ELEMENT?
• SPECTRUM SHOWING ONLY
CERTAIN COLORS OR SPECIFIC
WAVELENGTHS OF LIGHT.
• EMISSION OF LIGHT FROM AN
ATOM OCCURS WHEN AN ELECTRON
GOES FROM AN UPPER ENERGY
LEVEL TO A LOWER ONE.
BOHR’S ATOMIC
THEORY
LINE SPECTRA OF
VARIOUS ELEMENTS
USE OF LINE SPECTRA
IN TECHNOLOGY