1 / 25

Devil physics The baddest class on campus IB Physics

Devil physics The baddest class on campus IB Physics. Tsokos Lesson 4-8 Resolution. IB Assessment Statements . AHL Topic 11.4. and SL Option A.5., Resolution:

serenity
Download Presentation

Devil physics The baddest class on campus IB Physics

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Devil physicsThe baddest class on campusIB Physics

  2. Tsokos Lesson 4-8Resolution

  3. IB Assessment Statements AHL Topic 11.4. and SL Option A.5., Resolution: 11.4.1. Sketch the variation with angle of diffraction of the relative intensity of light emitted by two point sources that has been diffracted at a single slit. 11.4.2. State the Rayleigh criterion for images of two sources to be just evolved.

  4. IB Assessment Statements AHL Topic 11.4. and SL Option A.5., Resolution: 11.4.3. Describe the significance of resolution in the development of devices such as CD’s and DVD’s, the electron microscope and radio telescopes. 11.4.4. Solve problems involving resolution.

  5. Objectives • Understand what is meant by resolution • Apply the Rayleigh criterion

  6. Introductory Video

  7. Reading Activity Questions?

  8. Rayleigh Criterion • Diffraction is a way of life • Diffraction occurs in all lenses, including your eye • In diffraction there are maxima and minima • In order to see two objects as two separate objects, you need to separate the maxima for those objects

  9. Rayleigh Criterion • The Rayleigh criterion gives the minimum separation angle in which the two objects can just be resolved

  10. Rayleigh Criterion • The criterion is that the central maximum of one of the sources is formed at the first minimum of the second

  11. Rayleigh Criterion • Two unresolved sources • Two well-resolved sources

  12. Rayleigh Criterion • In diffraction, the first minima for a rectangular slit of width b occurs at: • The first minima for a circular slit of diameter b occurs at: • Therefore, objects can be resolved if their separation angle exceeds  (in radians!)

  13. Rayleigh Criterion • If two objects are separated by a distance s and their distance from the observer is d, then their angular separation (in radians) is given by

  14. Sample Problem The camera of a spy satellite orbiting at 200km has a diameter of 35 cm. What is the smallest distance this camera can resolve on the surface of the earth? (Assume a wavelength of 500nm)

  15. Microscopes • In microscopes, the object is in focus when it is at the focal length of the lens (hence the name) • The condition for resolution then becomes,

  16. Microscopes • In practice, f is of the same order of magnitude as b so f ≈ b • Therefore, in terms of order of magnitude, s ≈ λ • To resolve a small object of size s, the wavelength of light used, λ, must be the same order of magnitude as s or smaller

  17. Electron Microscope • In order to see an object as small as 0.01nm, we can’t use visual light • However, we can make use of the wave nature of electrons

  18. Electron Microscope • Sample Application: • We excite an electron to 105eV = 1.6 x 10-14 J (kinetic energy) • The mass of an electron is 9.1 x 10-31 kg

  19. Electron Microscope • Sample Application: • We excite an electron to 105eV = 1.6 x 10-14 J (kinetic energy) • The mass of an electron is 9.1 x 10-31 kg

  20. Electron Microscope • Sample Application: • We excite an electron to 105eV = 1.6 x 10-14 J (kinetic energy) • The mass of an electron is 9.1 x 10-31 kg • To resolve particles as small as 10-18m, electrons need energy in excess of 1000 GeV – hence the need for particle accelerators!

  21. ΣaryReview • Do you understand what is meant by resolution? • Can you apply the Rayleigh criterion?

  22. IB Assessment Statements AHL Topic 11.4. and SL Option A.5., Resolution: 11.4.1. Sketch the variation with angle of diffraction of the relative intensity of light emitted by two point sources that has been diffracted at a single slit. 11.4.2. State the Rayleigh criterion for images of two sources to be just evolved.

  23. IB Assessment Statements AHL Topic 11.4. and SL Option A.5., Resolution: 11.4.3. Describe the significance of resolution in the development of devices such as CD’s and DVD’s, the electron microscope and radio telescopes. 11.4.4. Solve problems involving resolution.

  24. Questions?

  25. Homework #1-7

More Related