3. Figure 2.2 is a photograph of an eyeball with the image of a boy in a doorway. Is the eye here acting as a lens or as a mirror? Explain. 6. A stamp collector uses a converging lens with focal length 28 cm to view a stamp 16 cm in front of the lens. (a)Where is the image located? (b) What is the magnification? Figure 2.1 Problem 2 Figure 2.2 Problem 3 137

Consider two thin lenses with focal lengths f1=10.0cm and f2=-15.0cm. The lenses are placed in contact. Calculate the equivalent focal length of the lenses. What is the image distance of an object placed 20.0cm from the lenses? Draw a diagram of the optical system and label the relevant quantities (s0,si,f).

An object is placed 40 cm in front of a thin lens. If an image forms at a distance 120 cm from the lens, on the opposite side as the object, what is the focal length of the lens, in cm? Your answer needs to have 2 significant figures, including the negative sign in your answer if needed. Do not include the positive sign if the answer is positive. No unit is needed in your answer, it is already given in the question statement.

A person with normal vision and a reference visual range of 250 mm uses a magnifying glass with a focal length of 102 mm. What magnification does the magnifying glass provide? Enter the result as a decimal number.

a) Calculate the distance between the final image and 22-cmcm-focal-length lens. b) Calculate the image height.

2. A Nikon 50mm camera lens is approximated as a cylinder with a diameter of 72mm and a length of 52.5mm. Determine the volume of the lens in cubic inches. Use correct significant figures in your answer. Assume 1cm = 10mm, 2.54cm = 1 in. Veylinder = ar2h

4. A convex (converging) lens produces a real, inverted image of an object that is magnified 2.20 times when the object is 37.0 cm from the lens. What is the focal length of the lens? cm

Information for image 1 m_a = 4.0000E+9 kg m_m = 2.8000E+8 kg v_ai x = -1100 m/s v_mi x = 2357 m/s v_fx = -8.73841×102 m/s Information for image 2 m_1 = 1.2840E+9 kg m_2 = 2.9960E+9 kg θ_1 = 32.2 degrees θ_2 = 61.5 degrees v_1 = 2.935×103 m/s What is the value of v_2? How much energy was released in the explosion?

A spherical mirror is polished on both sides. When the concave side is used as a mirror, the magnification is +2.6. What is the magnification when the convex side is used as a mirror, the object remaining the same distance from the mirror? If the object is inverted, then enter a negative number. Otherwise, enter a positive number. Number i Units >

An optician is designing a contact lens. The material has is an index of refraction of 1.45. In order to yield the prescribed focal length, the optician specifies the following dimensions: inner radius of curvature = +2.60 cm outer radius of curvature = +1.98 cm where the inner radius of curvature describes the surface that touches the eye, and the outer radius of curvature describes the surface that first interacts with incoming light. What is the focal length of this contact lens (in cm)?