DoITPoMS

Questions

Quick questions

You should be able to answer these questions without too much difficulty after studying this TLP. If not, then you should go through it again!

1. Explain why the image rotates when the strength of an electromagnetic lens is changed.

2. Which of these lens conditions gives the smallest convergence angle?

   	a	over-focus
   	b	in focus
   	c	under-focus

3. If an object is placed 1 mm from a (convex) lens of focal length 0.25 mm, where will the image be located?

4. How can chromatic aberrations be minimised in a TEM?

5. Which imaging technique requires the smaller objective aperture?

   	a	diffraction contrast
   	b	phase contrast

6. What is the minimum magnification needed to make visible the {111} planes in silicon?