James is helping Padfoot find more information about the Resurrection Stone. In the restricted section of the library, He finds a book written by Godric Gryffindor himself, but the writing is so small that she cannot read it without a magnifying glass. What kind of lens does a magnifying glass have? James has normal vision, and the book is placed 30 cm away from his face. To read Gryffindor’s script, he needs the image to be enlarged by a factor of 3. How far away from his face should he hold the magnifying glass, if it has a focal length of 15 cm?

An object is located 16.6 cm to the left of a diverging lens having a focal length f = −32.4 cm. What is the magnification of the image? Group of answer choices 0.661 2.13 0.346 1.17

It is your first day at work as a summer intern at an optics company. Your supervisor hands you a diverging lens and asks you to measure its focal length. You know that with a converging lens, you can measure the focal length by placing an object a distance ss to the left of the lens, far enough from the lens for the image to be real, and viewing the image on a screen that is to the right of the lens. By adjusting the position of the screen until the image is in sharp focus, you can determine the image distance s′s′ and then use the equation 1s+1s′=1f1s+1s′=1f, to calculate the focal length ff of the lens. But this procedure won'’t work with a diverging lens−−by itself, a diverging lens produces only virtual images, which can'’t be projected onto a screen. Therefore, to determine the focal length of a diverging lens, you do the following: First you take a converging lens and measure that, for an object 20.0 cmcm to the left of the lens, the image is 29.7 cmcm to the right of the lens.…

You are a marine biologist and want to pull a star fish out of a tank of water for testing. Looking from the top of the tank, where is the actual starfish compared to the image of the starfish that you see from the surface? Explain.

To fit a contact lens to a patient's eye, a keratometer can be used to measure the curvature of the cornea-the front surface of the eye. This instrument places an illuminated object of known size at a known distance p from the cornea, which then reflects some light from the object, forming an image of it. The magnification M of the image is measured by using a small viewing telescope that allows a comparison of the image formed by the cornea with a second calibrated image projected into the field of view by a prism arrangement. Determine the radius of curvature of the cornea whenp = 28.0 cm and M = 0.0140.

A camper is trying to start a fire by focusing sunlight onto a piece of paper. The diameter of the sun is 1.39 × 10⁹ m, and its mean distance from the earth is 1.50 × 1011 m. The camper is using a converging lens whose focal length is 10.3 cm. (a) What is the area of the sun's image on the paper? (b) If 0.752 W of sunlight pass through the lens, what is the intensity of the sunlight at the paper? (a) Number i (b) Number i Units Units

A 1.7 m tall person stands 8.0 m in front of a camera with a 5.0 cm focal length converging lens. What is the size of the image formed on film? 68.0 cm O 23.5 cm 2.7 cm 0.37 cm 1.1 cm 5.0 cm

A small object is placed to the left of a convex lens and on its optical axis. The object is 30 cm from the lens, which has a focal length of 15 cm. If the object is moved to a position 22 cm away, what will the image position be? (A positive value for p, or position, means the image is on the right side of the lens.)