Lesson 5 F and G
Section F
1. Review
a. Three laws of refraction for double concave lens
i. Any incident ray traveling parallel to the principal axis of a diverging lens will refract through the lens and travel in line with the focal point
ii. Any incident ray traveling towards the focal point on the way to the lens will refract through the lens and travel parallel to the principal axis.
iii. An incident ray that passes through the center of the lens will in effect continue in the same direction that it had when it entered the lens.
2. How to draw a ray diagram for a double concave lens
a. Draw three rays from the top of the object to the mirror. One should be horizontal, one should be diagonal and point towards the focal point, and one should pass straight through the center of the graph
b. Draw the refracted rays. The horizontal incidence ray should go diagonal, the vertical incidence ray should go horizontally, and the incidence ray going through the center of the diagram should continue to do so.
c. Because these rays do not converge behind the mirror, extend the refracted rays in front of the mirror. Do not do this for the ray that passes through the center of the graph. Use a dashed line to indicate the difference.
d. Locate the point at which these dashed lines intersect. Draw an upwards facing arrow from this point to the horizontal axis. This is your image.
Section G
1. Images produced by double concave lenses will be
a. Virtual
b. Upright
c. Reduced
1. Review
a. Three laws of refraction for double concave lens
i. Any incident ray traveling parallel to the principal axis of a diverging lens will refract through the lens and travel in line with the focal point
ii. Any incident ray traveling towards the focal point on the way to the lens will refract through the lens and travel parallel to the principal axis.
iii. An incident ray that passes through the center of the lens will in effect continue in the same direction that it had when it entered the lens.
2. How to draw a ray diagram for a double concave lens
a. Draw three rays from the top of the object to the mirror. One should be horizontal, one should be diagonal and point towards the focal point, and one should pass straight through the center of the graph
b. Draw the refracted rays. The horizontal incidence ray should go diagonal, the vertical incidence ray should go horizontally, and the incidence ray going through the center of the diagram should continue to do so.
c. Because these rays do not converge behind the mirror, extend the refracted rays in front of the mirror. Do not do this for the ray that passes through the center of the graph. Use a dashed line to indicate the difference.
d. Locate the point at which these dashed lines intersect. Draw an upwards facing arrow from this point to the horizontal axis. This is your image.
Section G
1. Images produced by double concave lenses will be
a. Virtual
b. Upright
c. Reduced