A person's prescription for bifocals is –0.35 diopter for distant vision and +3.10 diopters for near vision, the near vision being accomplished by inserts into the distant vision lens. What is the net power of the near vision correction?
a. 2.75 diopters
b. 3.10 diopters
c. 3.45 diopters
d. 1.085 diopters
e. More information is needed.
a
You might also like to view...
Future space stations will create an artificial gravity by rotating. Consider a cylindrical space station of 380 m diameter rotating about its axis. Astronauts walk on the inside surface of the space station
What rotation period will provide "normal" gravity? A) 28 s B) 39 s C) 6.2 s D) 4.4 s
Large, flat areas of sediments on the ocean basins are called
a. abyssal plains. b. guyots. c. continental shelves. d. atolls.
By comparing the two images, what can you conclude about Io's volcanoes?
A) Every black spot in the visible image has a bright spot in the infrared image, so all of Io's volcanoes were active when the photos were taken. B) There are more black spots in the visible image than bright spots in the infrared image, so many of Io's volcanoes were inactive when the photos were taken. C) There are more bright spots in the infrared image than black spots in the visible image, so new eruptions must have started after the visible photo was taken.
The mean free path of an oxygen molecule is 2.0 × 10-5 m, when the gas is at a pressure of 120 Pa and a temperature of 275 K
The molecular mass of oxygen is 32.0 g/mol and the Boltzmann constant is 1.38 × 10-23 J/K, Avogadro's number is 6.02 × 1023 molecules/mole, and the ideal gas constant is R = 8.314 J/mol ? K = 0.0821 L ? atm/mol ? K. Assuming that the molecules are moving at their root-mean-square speeds, the average time interval between collisions of an oxygen molecule is closest to A) 20 ns. B) 43 ns. C) 95 ns. D) 200 ns. E) 420 ns.