1. Card 2.

3. Half your height.

4. Moving it further creates a smaller virual image and closer a larger one. The full image is still there regardless of the distance.

7. 2 m/s

8. So that it can be read when view by a (rear view) mirror. Recall the mirror reverses an image.

10. Glass both reflects and transmitts light. The typical window transmitts a great deal more light than it reflects. If the outside light is considerably greater then the inside light, the amount reflected back is more than the amount transmitted from inside to out. An outside observer will only see what is reflected while the inside observer will only see what is transmitted.

17. The same as it did going in, white.

20. Aim below the image with a spear, the image appears closer to the surface than the actual object. Aim directly at the fish is using a laser, since the light waves going into the water will be deflected by the same angle as the light waves coming out.

22. It sees the sky. Reflection occurs if the angle is greater than 48^o (the critical angle)

27. The shadow will be at the center of the circle. The airplane will lie directly between the sun and the water drops/clouds.

29. A lens can be thought of a series of prisms which refracts light (broadens it into a spectrum). Most of the light waves within the circle combine to form white while those around the outside do not. Allowing the different colors to be seen.

33. Must be between the focal point and the lense. No, a diverging lense has no converging light.

35. For objects at extreme (infinite) distances light comes to a focus at the focal point. The film is one focal length behind the lens in this case. If the object is nearer, the object will come into focus past the focal length, hence the film should be further than one focal length.

36. As the moon is viewed through most telescops it is inverted, due to the lenses/mirrors used. The view then seen through the telescope matches what is viewed on the map.

37. The intensity of the light is cut in half. The full image is still there though.

41. 84.6% throught 2 panes.

43. Since blue light has a higher frequency than red, photons associated with blue light have greater energy. Since both beams have the same energy, there must be more photons in red light.

45. The amount of energy ultraviolet light transfers to the skin is much greater than the amount vilible light transfers.

46. Brightness. The brighter the light, the more photons. The more photons stricking a material the more electrons that may be ejected. The frequency of light effects the energy of the ejected electrons.

47. In some automatic doors a beam of light shines across the enterence to strike a dector on the other side. This produces a current. As you block the beam the current changes, this change in current signals the door to open.