The resolving power of a refracting telescope increases with the diameter of the spherical objective lens. In reality, it is impractical to increase the diameter of the objective lens beyond approximately 1 m. Why? a. The resultant sagging of the mirror will cause spherical aberration. b. The resulting increase in light scattering from the surface of the objective lens will blur the image. c. If the objective lens is too large, it is difficult to keep it clean. Od. The increasing size of the objective lens will cause chromatic aberration to grow worse than spherical aberration. e. The spherical objective lens should be replaced by a paraboloidal objective lens beyond a 1-m diameter.

Which of the following is not a problem for refracting telescopes? O A. Different wavelengths of light are focused at slightly different locations. O B. The quality of the glass lens in transparency and in the shape of both surfaces must be high. C. The secondary mirror blocks some of the light passing through the primary lens. D. The primary lens can only be supported at the edges making deformation of large lenses difficult to avoid.

1. Which of following statement regarding non-linear optics is incorrect? A. Refractive index can depend on light intensity. B. Two light beams are independent and cannot control each other. C. It can produce second harmonic generation with light frequency doubled (2w). D. It can produce sum-frequency generation of two incident light beams (@3 = w1 + w2). %3D

A camera lens used for taking close-up photographs has a focal length of 21 mm. The farthest it can be placed from the film is 33.3 mm. a. What is the closest object that can be photographed?  mm b. What is the magnification of this closest object?  X