Photoelectric+Effect

=Part 1: 2/27/12= OK... Got it. Some of these responses, especially the scientists, are perfunctory. I hope you know the details better than these explanations demonstrate. ~EB

= Part 2: 2/28/ = The "Show your Work" in all caps was supposed to clue you in... You must show work for all calculations, as always: equations used, numbers plugged in, etc.

= Part 3: 2/29/12 =

>> E=hf-work >> 0=6.63E-34*(3E8/765E-7)- work >> work=1.625 eV >> >> E=hf-work >> 0=(6.63E-34)f-1.96*1.6E-19 >> f=4.73E14 >> C=lambda*f >> 3E8=4.73E14*lambda >> lambda=6.34E-7 >> E=hf-work >> E=(6.63E-34)(3E8/425E-9)-1.96*1.6E-19 >> **E=1.544E-19 J**
 * 1) The line on the graph of current to intensity can be described as _**linear with large positive slope.**
 * 2) The line on the graph of energy to frequency can be described as _**linear (slope= planck's constant, y-int=work function)**
 * 3) At a __frequency below__ the frequency required to overcome the work function, increasing the light intensity causes the current to //increase / decrease / **remain the same.**//
 * 4) At a __frequency above__ the frequency required to overcome the work function, increasing the light intensity causes the current to //**increase** / decrease / remain the same.//
 * 5) Old darkrooms (for developing film) were once illuminated with a feint red light (765nm). If this was the limit of the silver compound used in the film, solve for the work function of the silver compound. __**1.625** eV____J__
 * Consider the following scenario: On a partly cloudy day you find that a household photovoltaic array outputs 2.4 amps of current. If the clouds part and the sun comes out, exactly doubling the amount of light incident on the PV array, we should expect the array to output //2.4 A / 4.8 A / more than 4.8 A / less than 2.4 A / **between 2.4 and 4.8 A**//.
 * 1) The work function for cesium is 1.96 eV. Find the cutoff wavelength for the metal_**6.34E-7** __m__
 * What is the maximum kinetic energy for the emitted electrons when 425 nm light is incident on #7’s metal? J

> E=hf-work > 3.7*1.6E-19=6.63E-34(3E8/425E-9)-work > work=1.24E-19 > > E=6.63E-34(3E8/425E-9)-1.24E-19 > **E=3.44E-19= 2.15eV**
 * 1) In certain metal, the stopping potential is found to be 3.70 V. When 235 nm light is incident on the metal, electrons are emitted. What is the maximum kinetic energy given to the electrons in eV and J? _ eV__ _ J

10.Stars vary in color. Which color indicates the hottest surface temperature of a star? 11.Which of the following ojbects, all moving at the same speed, would have a de Broglie wavelength associated with them that would be larger than that of a proton travelling a the same speed? 12.When green light shines upon a given metal, it emits phtoelectrons. Which of the following will also produce photoelectric emission, using this same metal? 13.Ultraviolet light shines upon a sheet of zinc metal, and photoelectrons are emitted. If the intensity of the light is increased, 14.Consider the following frequencies of electromagnetic radiation. Which photon has the greatest energy? 15.Compared to a photon of blue light, a photon of red light has 16.An electron is confined to a box of sides L and it has a definite speed. If the walls of the box were to move inward so that the box shrinks, the electron 17.The idea of packets or quanta of energy originated with 18.A matter wave 19.Which of the following does not demonstrate the wave nature of matter? 20.When doing the photoelectric effect experiment, >> **Wavelength** >> **Work function of metal**
 * 1) Red
 * 2) Orange
 * 3) Yellow
 * 4) **Blue**
 * 1) **An electron**
 * 2) A neutron
 * 3) A bacteria
 * 4) A baseball
 * 1) **Low intensity blue light**
 * 2) Low intensity red light
 * 3) High intensity red light
 * 4) high intensity yellow light
 * 1) The electrons will have less energy.
 * 2) The electrons will have more energy
 * 3) **More electrons will be emitted**
 * 4) Fewer electrons will be emitted.
 * 1) 6.6 x 10-34 Hz
 * 2) 6.6 x 10-4 Hz
 * 3) 6.6 x 104 Hz
 * 4) **6.6 x 1018 Hz**
 * 1) More energy
 * 2) **Less energy**
 * 3) Shorter wavelength
 * 4) The same wavelength
 * 1) Would speed up
 * 2) Would slow down
 * 3) **Would move with the same speed**
 * 4) Would exhibit none of the above.
 * 1) Louis de Broglie
 * 2) **Max Planck**
 * 3) Werner Heisenberg
 * 4) Erwin Schrodinger
 * 1) Applies only to “massless” particles
 * 2) Applies only to a photon
 * 3) **Has a wavelength inversely related to its momentum**
 * 4) Has a wavelength directly related to its momentum
 * 1) The cloud model of the electron
 * 2) The two slit interference pattern
 * 3) **An electron in motion in a conducting wire (circuits)**
 * 4) Electron diffraction
 * 1) What determines the amount of kinetic energy photoelectrons will have?
 * 1) What determines the number of photoelectrons emitted from a metal?