April 25 AP Physics

In:A wire loop of radius 0.50 m lies so that an

external magnetic field of magnitude 0.20 T is perpendicular to the loop. The field reverses its direction, and its magnitude changes to 0.30 T in 1.5 s. Find the magnitude of the average induced emf in the loop during this time.

Objective: To comprehend: Quantum physics

Photons, the photoelectric effect, Compton scattering

Atomic physics Atomic energy levels Wave-particle

duality

Atomic and Nuclear physics Quantum physics

Photons, the photoelectric effect, Compton scattering Atomic physics

Atomic energy levels Wave-particle duality

Nuclear physics: Nuclear reactions (including conservation of mass

number and charge) Mass-energy equivalence

"There is nothing new to be discovered in physics now. All that remains is more and more precise measurement"

Attributed to William Thomson, 1st Baron Kelvin 1900

http://physics.hpa.edu/physics/apphysics/sims/apb51%20Photons%20and%20photoelectric%20effect/5A1_pt2.swf

Black body radiation and Max Planck’s quantum theory German physicist Founder of quantum

theory Nobel prize 1918 http://physics.hpa.edu/physics/apphysics/sims/

apb51%20Photons%20and%20photoelectric%20effect/5A1_pt3.swf

Photoelectric effect:

Einstein and the photoelectric effect

German born physicist 1905 “Miraculous Year”

Special theory of relativity Mass/energy equivalency Photoelectric effect Brownian motion

Nobel prize 1921 http://physics.hpa.edu/physics/apphysics/sims/apb51%20Photons

%20and%20photoelectric%20effect/5A1_pt4.swf http://physics.hpa.edu/physics/apphysics/sims/apb51%20Photons

%20and%20photoelectric%20effect/5A1_pt5.swf

http://physics.hpa.edu/physics/apphysics/sims/apb51%20Photons%20and%20photoelectric%20effect/5A1_pt6.swf

Graph for different metals

E = hf = pcKmax = hf - Φ

E = energyf = frequency

K = kinetic energyh= Planck’s constant

6.626 x 10-34 j.s

Lithium has a work function of 2.30 eV. If 400-nm light is incident what is the maximum kinetic energy of the photoelectrons.

Arthur H. Compton American

physicist Discovered the

phenomena called Compton scattering.

Nobel prize 1927

http://physics.hpa.edu/physics/apphysics/sims/apb51%20Photons%20and%20photoelectric%20effect/5A1_pt7.swf

Neils Bohr Danish Physicist Explained atomic spectra

with his model of the atom Nobel prize 1922

A stellar spectrum shows three absorption lines of hydrogen produced as electrons move from the n=2 state to higher energy levels (n=3, n=4, n=5) what are the wavelengths and colors of the three lines missing from the continuous spectrum?

Louis de Broglie French Physicist Postulated that

matter can behave as a waves

Nobel prize 1929

If a wave can be a particle, can a particle be a wave?

λ=h

p

If the wavelength of an electron is 5.00 × 10−7 m, how fast is it moving? (b) If the electron has a speed of 1.00 × 107 m/s, what is its wavelength?

Out:Why do you think that physicists in 1900

thought they had discovered everything?