Physics Core/AP 1 and 2

Homework

# Physics 25: 7-12 Resolution and Microscope

## Homework

Text Reading: Giancoli, Physics - Principles with Applications, Chapter 25: Sections 7 to 12

#### Study Points

• Section 7: Resolution is the ability of a lens to show close objects as two distinct points. The maximum resolution is depends on the diameter of the lens and the wavelength of light and is given by the Rayleigh criterion.
• Section 8: The resolving power also depends on the focal length.
• Section 9: There are practical limits to human eye and microscope magnifications because of the wavelength and diameter dependencies of resolution. Light microscopes above 1000X suffer from too much chromatic aberration to be useful.
• Section 10: The resolving power of a lens can be increased by using computers to interpret information from the source through the lens to reduce aberration.
• Section 11: X-ray diffraction can be used to analyze rays scattered by the surfaces of very small objects, such as protein molecules.
• Section 12: Modern X-ray techniques such as CT (computed tomography) and CAT (computer-assisted tomography) allow non-destructive exploration of human tissues, and are important tools for diagnosis and treatment of disease and injury.

### Key Equations

ConceptFormulaApplication
Rayleigh criterion Minimum angular separation
Resolving Power Minimum linear separation

### Web Lecture

Read the following weblecture before chat: Telescopes

### Study Activity

Use the Telescope simulator to see how changing eyepiece and objective size optimize viewing for different types of objects.

### Chat Preparation Activities

• Forum question: The Moodle forum for the session will assign a specific study question for you to prepare for chat. You need to read this question and post your answer before chat starts for this session.
• Mastery Exercise: The Moodle Mastery exercise for the chapter will contain sections related to our chat topic. Try to complete these before the chat starts, so that you can ask questions.

### Chapter Quiz

• Required: Complete the Mastery exercise with a passing score of 85% or better.
• Go to the Moodle and take the quiz for this chat session to see how much you already know about astronomy!

### Lab Work

If you want lab credit for this course, you must complete at least 12 labs (honors course) or 18 labs (AP students). One or more lab exercises are posted for each chapter as part of the homework assignment. We will be reviewing lab work at regular intervals, so do not get behind!