Refraction of Light EM lesson 8

 Thicker in the center than at the edges  Have positive focal lengths  Converge parallel rays of light that pass through them

 If an object is beyond C, the image is real, inverted, and smaller  If the object is at C (or 2F), the image is real, inverted, and the same size as the object  If the object is between C and F, the image is real, inverted, and enlarged.  If the object is at F, no image is formed

Virtual Images Formed By a Convex Lens  A virtual image is formed if the object is located between the focus and the lens.

 if object is between F and the lens, image formed is virtual, upright and larger F F

 Thinner at the center than the edges  Have negative focal lengths and diverge parallel rays of light passing through them The focal length depends on the index of refraction and curvature

 As n (index of refraction) increases, focal distance decreases  As curvature increases, focal distance decreases also

 concave lens will only produce a virtual image F Image formed is virtual upright and smaller than original object

 to tell whether an object is real or virtual, erect or inverted, enlarged or diminished – DO THE MATH  Real image – d i > 0  Virtual image – d i < 0  Erect image – h i > 0  Inverted image – h i < 0  Enlarged image – M > 1  Diminished image – M < 1