HW

Have a look at these pages:

Two things for homework.

Thing 1 - try these problems:

You have a lens with focal length 24 cm.  A plastic toy is located 50 cm from it.  Find the following:

a.  type of lens.  Recall that the sign of the focal length means something.

b.  location of image (di).  Use the lens equation.

c.  type of image (real or virtual).  Hint - a positive di means real; negative di means virtual.

d.  magnification of image (mag = - di/do)

e.  whether image is right-side up (positive magnification) or upside-down (negative magnification)

f.  whether image is larger (absolute value of magnification is bigger than 1) or smaller than object

g.  location(s) where you could move object and get NO image at all

h.  location(s) where you could move object and get only virtual image(s)

Thing 2 - Have a look at these pages.  Come to class with a definition of "diffraction" of light.

http://www.physicsclassroom.com/Class/light/u12l1a.cfm

http://www.physicsclassroom.com/Class/light/u12l1b.cfm