_______________physics Matter is a____________________ Light is a _________________.

2. _______________physics • Matter is a____________________ • Light is a _________________. Classical particle wave This is "everyday" physics that deals with objects that are relatively 1. _____________  bigger than _____________ 2. _____________  v << _____ large atoms slow c Einstein _______________ modified classical physics so that it would give more accurate results when speeds _______________________________ and for________________. His theories are called the ________________ and ________________ Theories of _________________________ . were close to c gravity Special General Relativity

4. Modern • _______________ physics modified physics to deal with • _________________________ on the scale of ___________ . • According to this theory: • Matter can act like a___________________________. • Light can act like a___________________________. atoms tiny objects particle or a wave particle or a wave Ex: Light in the classical view acts like a ___________ whose _________________ determines its energy: wave amplitude brighter • _______________  more____________ energy

5. Ex: The ___________________ effect showed that light can act like a ______________________ . photoelectric particle shine light electrons e- “photo…” “…electric” zinc

6. Duality: wave particle

7. Einstein _____________________________ for a paper that explained the photoelectric effect by assuming light acted like ______________. The higher its _______________ the greater the energy of the light particle. Bright light consists of ___________ particles. won a Nobel Prize frequency particle many dim red low _______________ light:  1_______ energy particle cannot eject an e- none of these many _______ energy particles could eject an e- low bright red ________________light: dim violet high ________________light:  1_______ energy particle can eject 1 e- each of these many ________ energy particles could eject an e- high bright violet ________________light:

9. The ______________ (basic unit) of electromagnetic energy (light) is called a _______________ . It has no mass, but carries ______________ and ________________ . Its energy is given by: quantum photon energy momentum Eph = where h = = Ex: What is the relationship between Eph and f? Eph f What quantity does the slope of the line?

10. See page 1 of Reference Tables

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12. The ______________ (basic unit) of electromagnetic energy (light) is called a _______________ . It has no mass, but carries ______________ and ________________ . Its energy is given by: quantum photon energy momentum Eph = hf where h = = Planck's constant 6.63 x 10-34 J·s Ex: What is the relationship between Eph and f? Eph f h What quantity does the slope of the line? Eph/f = ?

14. Ex: What is the relationship between Eph and l? • Start with the equation: • Substitute c in for v: • Solve for f: • Substitute in the equation for v = fl c = fl f = c/ l Eph= hf Eph= hc/l Ex: What is the relationship between Eph and l in graph form? Eph l The greater the wavelength, the ___________ the energy.

16. Ex: What is the relationship between Eph and l? • Start with the equation: • Substitute c in for v: • Solve for f: • Substitute in the equation for v = fl c = fl f = c/ l Eph= hf Eph= hc/l Ex: What is the relationship between Eph and l in graph form? Eph l less The greater the wavelength, the ___________ the energy.

17. Ex: Find the energy of a blue light photon in joules. Eph = hf = hc/l = (6.63 x 10-34 J·s) (???) Convert the answer to electronvolts (eV). page 1 of RT: 1 eV = ________________ J

18. Choose f = 6.5 x 1014 Hz

19. Ex: Find the energy of a blue light photon in joules. Eph = hf = hc/l = (6.63 x 10-34 J·s) (6.5 x 1014 Hz) = 4.3 x 10-19 J Convert the answer to electronvolts (eV). page 1 of RT: 1 eV = ________________ J

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21. Ex: Find the energy of a blue light photon in joules. Eph = hf = hc/l = (6.63 x 10-34 J·s) (6.5 x 1014 Hz) = 4.3 x 10-19 J Convert the answer to electronvolts (eV). 1.6 x 10-19 See page 1 of RT: 1 eV = ________________ J _______1 eV_______ 1.6 x 10-19 J Eph = 4.3 x 10-19 J x Eph = 2.7 eV

22. _____________ theory - ____________________ energy is emitted from and absorbed by _______________ in _____________ amounts or ________________ . ( ______________ means "separate, individual pieces.") Quantum electromagnetic matter discrete "packets" Discrete after: absorption before: Ex: _______________ of a photon atom has ______ energy atom more emission Ex: _____________ of a photon after: before: atom has _______ energy atom less

23. Compton Ex The ____________Effect: X-rays scatter off electrons. 0 e- at rest  KE =____ v=c before collision: x-ray _______ photon now has KE e- ____________ after collision: The scattered photon now has _______ energy. So its f is _______ and its l is ______________ less less c longer momentum energy Both _________________and ______________ are conserved.

25. In sum, light can act like a __________________ or like a ____________ . Which one it acts like depends on the situation. When light interacts with.. particle wave … __________ , it acts like a _________________ Examples: 1/ __________________ 2/ __________________ … ___________ , it acts like a __________________ Examples: 1/ __________________ 2/ __________________ 3/ __________________ light atoms wave particle interference absorption diffraction emission collisions Even when it is described as a photon, we still use __________ properties such as _______________ and _________________ to describe it. frequency wave wavelength

26. Electron charge: In 1909, Millikan sprayed drops of ________ into an _______________ field E. oil electric qE Fe =___ oil drop mg Fg =_____ By suspending the oil drop then letting it fall, he was able to discover that the oil drops always carried an ___________________________ of the fundamental charge = ______________________ (the ______________ of charge). which is the charge on 1 _____________ or _____________ .  Charge is __________________ . integer multiple 1.6 x 10-19 C quantum electron proton quantized