When an object is placed 15 cm from a lens, a virtual image is formed. Which of the following statements must be true? I. The lens may be a convex or concave II. If the image is upright the lens must be a diverging lens. III. If the lens is diverging lens, the focal length must be less than 15 cm. O I only O I, II, and I I and II O I and II

The image is formed on the retina even when the distance of the object from the eye increases The lens of the eye becomes thinner and the focal length increases. O The lens of the eye becomes thicker and the focal length decreases. The lens of the eye becomes thinner, and the focal length decreases. с The lens of the eye is not affected and remains the same thickness. O

An object is 8.5 cm away from a thin convex lens with focal length of f1 = 3.1 cm. 8.0 cm away from the first convex lens is a second convex lens on the same optical axis with focal length of f2 = 2.1 cm. a) Draw a principal ray diagram for the optical system including the different focal lengths, image and object distances. b) Describe the nature (real or virtual) and orientation of the final image relative to the object. c) Calculate the position of the final image after the two lenses and its magnification.

1. Assume that a camera has a bi-convex lens. Should you move the lens toward or away from the sensor in order to zoom in (magnify)? 2. A camera has a bi-convex lens whose focal length is 50mm. The lens’s range of motion is 5.56mm starting from 50mm from the sensor and moving away. What are the minimum and maximum possible object positions for which the image is in focus? 3. For the camera in the previous question, when a 300mm tall object is at the minimum distance, will it fit on a Canon APS-C sensor? Hint: Look up the size of this camera sensor. 4. See Figure 10.7! A circular piece of glass (n=1.5) has been cut in half as shown and is being used as a lens for a set of five parallel rays. The angles at which the rays are incident on the circular side of the lens are shown, and the image is drawn to scale. First, calculate the 5 angles of refraction for each of the 5 angles of incidence, respectively. Second, use a protractor to draw the refracted rays such that they intersect the…