Recitation nine

Recitation nine - Recitation eight Question 1 We have seen centered cells in three dimensions(bcc and ffc e.g but they also exist in two dimensions

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Recitation eight Question 1 We have seen centered cells in three dimensions (bcc and ffc e.g.) but they also exist in two dimensions. Consider the above wallpaper design on the left . It has both rotational and translational symmetry. 1. Draw the smallest unit cell possible. (Note: the angles between the two unit vectors are not 90 degrees in what is called the primitive cell ) 2. How many left and right crescents are there in a unit cell? 3. Are the two basic unit vectors of the same length? 4. Draw a vertical line around which the pattern is a mirror image of itself 5. Do the same in the horizontal direction 6. What angle do these two mirror lines make with each other? 7. Now construct the smallest unit cell possible that has its unit vectors in the direction of the mirror lines 8. How many left and right crescents are there in this centered cell? 9. Are the unit vectors of the centered cell of the same length? 10. Draw second horizontal mirror, one cell shifted from the first and draw a parallel line
Background image of page 1

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

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 11/08/2011 for the course CH 101 taught by Professor Bigham during the Spring '08 term at N.C. State.

Page1 / 2

Recitation nine - Recitation eight Question 1 We have seen centered cells in three dimensions(bcc and ffc e.g but they also exist in two dimensions

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online