The first known telescopes, used around 1600, consisted of a lens and an eyepiece. today, telescopes are often computer controlled and consist of a complicated array of sophisticated lenses. which statement correctly describes how telescopes have changed over time? a.)the telescopes of the 1600s were used until the year 2000, when a more sophisticated telescope was built. b.)the telescopes of the 1600s were gradually improved upon over time, resulting in the telescopes that are available today. c.)the telescopes of the 1600s were used until the year 1900, when a more sophisticated telescope was built that was used until the year 2000. d.)the telescopes of the 1600s were abandoned after about 50 years, and the technology was completely replaced.

Two nitro no2 groups are chemically bonded to a patch of surface. they can't move to another location on the surface, but they can rotate (see sketch at right). it turns out that the amount of rotational kinetic energy each no2 group can have is required to be a multiple of ε, where =ε×1.010−24 j. in other words, each no2 group could have ε of rotational kinetic energy, or 2ε, or 3ε, and so forth — but it cannot have just any old amount of rotational kinetic energy. suppose the total rotational kinetic energy in this system is initially known to be 32ε. then, some heat is removed from the system, and the total rotational kinetic energy falls to 18ε. calculate the change in entropy. round your answer to 3 significant digits, and be sure it has the correct unit symbol.

Calculate the number of molecules present in 0.750 mol of mgo.

40dm3 of gas at 760 torr are heated from 5°c to 50°c what is the new volume