You are designing contact lenses for someone whose near point is 43 cm. What focal length lens should you prescribe so that an object can be clearly seen when placed at 25 cm in front of the eye?
a. 43 cm
c. -15 cm
b. 18 cm
d. 60 cm
D
You might also like to view...
An unusual lightning strike has a vertical portion with a current of ?400 A downwards. The Earth's magnetic field at that location is parallel to the ground and has a magnitude of 30 ?T. In N, the force exerted by the Earth's magnetic field on the 25 m-long current is
a. 0. b. 0.012 N, East. c. 0.012 N, West. d. 0.30 N, West. e. 300 N, East.
Any naturally occurring, inorganic, crystalline substance with a fairly definite chemical composition is called a(n)
a. element. b. compound. c. rock. d. mineral.
Which of the following is false?
a. Alpha Orionis is apparently brighter than Beta Orionis. b. Beta Orionis is apparently brighter than Alpha Orionis. c. Rigel is apparently brighter than Betelgeuse. d. None of the choices are false.
Center of Mass: In the figure, four point masses are placed as shown. Assume that all the numbers in the figure are accurate to two significant figures. What are the x and y coordinates of the center of mass (or center of gravity) of this arrangement?
A. (2.2 m, 2.6 m) B. (2.2 m, 2.7 m) C. (2.3 m, 2.6 m) D. (2.3 m, 2.7 m) E. (2.3 m, 2.8 m)