A compound microscope has a 18-cm-long barrel and an objective lens with a focal length of 8.0 mm
What is the focal length of the eyepiece to give a total magnification of 240? It is adjusted for minimum eyestrain for persons with a near point of 25 cm. A) 1.3 m
B) 1.5 cm
C) 1.9 cm
D) 2.1 cm
E) 2.3 cm
D
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As the angle of incidence is decreased for a ray incident on a reflecting surface, the angle between the incident and reflected rays ultimately approaches what value?
a. 90° c. 45° b. 180° d. zero
An ice dancer with her arms stretched out starts into a spin with an angular velocity of 1.00 rad/s. Her moment of inertia with her arms stretched out is 2.48 kg 
What is her angular velocity when she pulls in her arms to make her moment of inertia 1.40 kg 
?
A. 2.67 rad/s B. 2.45 rad/s C. 2.03 rad/s D. 1.90 rad/s E. 1.77 rad/s
During each cycle of operation, a refrigerator absorbs 230 J of heat from the freezer and expels 356 J of heat to the room. How much work input is required in each cycle?
A) 712 J B) 586 J C) 460 J D) 310 J E) 126 J
The lesser amount of a substance in a solution is generally called the
a. solute. b. salt. c. solvent. d. alloy.