# Blackbody radiation and Light: a wave or a particle?

## Presentation on theme: "Blackbody radiation and Light: a wave or a particle?"— Presentation transcript:

Blackbody radiation and Light: a wave or a particle?

Increasing Voltage Light Bulb Demo Quick Review

scienceblogs.com Black Body Radiation: Refresher T= temperature in kelvin max = wavelength of maximum intensity in mm

BLACKBODY RADIATION Sun’s temperature: 5700 K scienceblogs.com What does this mean about the types of light the sun emit? A)UV only B) Visible Only C) IR only D) UV, Visible and IR E) I don’t know

BLACKBODY RADIATION Sun’s temperature: 5700 K scienceblogs.com What color is the sun? A) Yellow B) Orange C) Purple D) All the colors, which we see as white E) All the colors, which we see as black

BLACK BODY RADIATION scienceblogs.com Blackbody radiation depends only on temperature of object 2700-3300K Given this information about a light bulb, why are incandescent bulbs inefficient light sources?

BLACKBODY RADIATION Sun’s temperature: 5700 K

DOUBLE SLIT EXPERIMENT: YOUNG It’s a wave! http://www.olympusmicro.com

DOUBLE SLIT EXPERIMENT Problem 4) Double slit experiment. Draw what the expected out come of each situation B) Light is a particle, 2 slits.

PROBLEM 5: VISUALIZATION EXERCISE: HTTP://PHET.COLORADO.EDU/EN/SIMULATION/PHOTOELECTRIC PHOTOELECTRIC EFFECT: EINSTEIN It’s both! ACTIVITY DISCUSSION:

PHOTOELECTRIC EFFECT The work function for magnesium is 5.90x10 -19 J. 6) What is the threshold frequency? 7) Calculate the kinetic energy of the ejected electron if the light of frequency 1.80x10 15 is used for irradiating the metal? 8) Calculate the kinetic energy and velocity of the ejected electron if the light of frequency 1.80x10 15 s -1 is used for irradiating the metal.