Rays of light incident on a lens and parallel to the principal axis of the lens coverage? a. in front of the lens. b. at the focal point of the lens. c. in back of the lens. d. at the center of curvature of the lens.

How can waves travel through ground?

You have two photos of a person walking. one shows the person at the corner of third and main streets, the other shows the person at the corner of tenth and main streets. there are lampposts at every corner in this town, and the first picture shows it to be 10: 32: 00 exactly. the second picture shows it to be 10: 49: 30. you know three facts: (1) all of the clocks are synchronized; (2) there are exactly 12 equal-sized blocks per kilometer in this town; and (3) the streets that cross main in this area are numbered consecutively, with no interruptions. what is the person’s average speed in kilometers per hour?

Which form of pure carbon is so hard that it can be used in cutting tools?