33. Geometric Optics

If an object is placed within the focus of a converging lens (it's at a distance of less than the focal length), will a real image form? If so, does it form at a distance less than or greater than the focal length?

If an object is placed within the focus of a diverging lens (it's at a distance of less than the focal length), where will the image form? If so, does it form at a distance less than or greater than the focal length?

(I) (a) What is the power of a 26.5-cm-focal-length lens? (b) What is the focal length of a -6.25 -D lens? Are these lenses converging or diverging?

(II) A 105-mm-focal-length lens is used to focus an image on the sensor of a camera. The maximum distance allowed between the lens and the sensor plane is 132 mm. (a) How far in front of the sensor should the lens (assumed thin) be positioned if the object to be photographed is 10.0 m away? (b) 3.0 m away? (c) 1.0 m away? (d) What is the closest object this lens could photograph sharply?

(I) A sharp image is located 373 mm behind a 235-mm-focal-length converging lens. Find the object distance (b) by calculation.