In recent decades, manufacturers of thin lenses for cameras talk a lot about "aspherical lenses." These lenses are harder to manufacture and so more expensive. What advantage do they provide that makes it worth paying more for them. Hint: One application is in making lenses of the same focal length but larger than the spherical counterpart.

 

2. (4 pts) Consider a glass convex lens both sides of which have a radius of curvature of 100mm. The lens will be used in air.

a. For using the lens equations, what are the signs of the radii of curvature for the two sides?

b. What is the focal length of the lens? Include the sign.

c. Light coming in from very far away will be focused how far from the lens?

d. A virtual image will be formed for objects how far from the lens?

e. When this lens forms a real image, will the image be erect or inverted?

f. What is the distance and magnification of the image produced for a real object 20mm from the lens?

3. (4 pts) Consider two thin lenses A and B placed so that light from an object on the left hits lens A and then lens B. Lens A is diverging and has focal length -200mm. Lens B is converging and has focal length 50mm. It is placed 100mm to the right of lens A. An object is placed 100mm to the left of lens A. What is the resulting image position (with respect to the position of lens B), type (real or virtual) and magnification (including sign)?