HW03-solutions - vasquez(mpv244 HW03 Atomic Theory Part I...

Info icon This preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
vasquez (mpv244) – HW03: Atomic Theory Part I – shear – (52375) 1 This print-out should have 27 questions. Multiple-choice questions may continue on the next column or page – find all choices before answering. Note the due date is Tuesday so you will get an answer key to study for the exam. A second homework will be posted tonight. 001 10.0 points Which color in the rainbow has the longest wavelength? 1. green 2. yellow 3. orange 4. red correct 5. blue Explanation: Ordered by wavelengths, blue < green < yellow < orange < red 002 10.0 points What is the correct order of decreasing en- ergy? 1. microwaves, visible light, x-rays, γ -rays, ltraviolet light 2. microwaves, visible light, ultraviolet light, x-rays, γ -rays 3. visible light, microwaves, x-rays, γ -rays, ltraviolet light 4. γ -rays, x-rays, ultraviolet light, visible light, microwaves correct 5. visible light, ultraviolet light, microwaves, x-rays, γ -rays Explanation: γ -rays > x-rays > ultraviolet light > visible light > microwaves 003 (part 1 of 2) 10.0 points When sodium is heated, a yellow spectral line whose energy is 3 . 37 × 10 - 19 J/photon is produced. What is the frequency of this light? 1. none of above 2. 6 . 626 × 10 - 34 Hz 3. 1 . 602 × 10 - 19 Hz 4. 5 . 09 × 10 14 Hz correct 5. 3 . 0 × 10 8 Hz 6. 5 . 09 × 10 - 34 Hz 7. 3 . 37 × 10 11 Hz 8. 3 . 37 × 10 19 Hz 9. 5 . 9 × 10 - 7 Hz Explanation: E photon = 3 . 37 × 10 - 19 J / photon ν = ? E photon = h ν ν = E photon h = 3 . 37 × 10 - 19 J 6 . 626 × 10 - 34 J · s = 5 . 09 × 10 14 Hz 004 (part 2 of 2) 10.0 points What is its wavelength? 1. 6 . 626 × 10 - 34 m 2. none of above 3. 1 . 602 × 10 - 19 m 4. 3 . 0 × 10 8 m 5. 5 . 09 × 10 14 m 6. 5 . 9 × 10 - 7 m correct Explanation: λ = ? c = λ ν
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
vasquez (mpv244) – HW03: Atomic Theory Part I – shear – (52375) 2 λ = c ν = 3 . 0 × 10 8 m/s 5 . 09 × 10 14 Hz λ = 5 . 9 × 10 - 7 m 005 10.0 points What key result from the photoelectric effect showed that classical physics did not work on the atomic scale? 1. Light intensity and electron current were related. 2. All metals are reflective. 3. Different metals showed different behav- iors. 4. Radiation below a certain frequency, no matter how intense, would not cause electron emission. correct 5. The effect is not observed when a gas is introduced into the vacuum chamber. Explanation: When electromagnetic radiation (light) of sufficient minimum energy strikes a metal cathode, electrons are knocked off its sur- face, travel to an anode, and form a current through a circuit. Two important observations were: 1) Electrons can be ejected only if the light is sufficiently energetic. Electron ejection is independent of time or intensity. The mini- mum energy varies by element. 2) The current increases with increasing intensity and is independent of color. Therefore, light is made up of photons, each having a particular amount of energy that can be transferred to an electron during a colli- sion. If the energy is equal to or greater than the amount needed to liberate the electron, it can escape to join the photoelectric current.
Image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern