The angular magnification of a refracting telescope is 40. When the object and final image are both at infinity, the distance between the eyepiece and the objective is 143.5 cm. The telescope is used to view a distant radio tower
The real image of the tower, formed by the objective, is 6.0 mm in height. The focal point of the eyepiece is positioned at the real image. What is the focal length of the objective lens?
A) 139 cm B) 141 cm C) 140 cm D) 138 cm
C
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A soft magnetic material has which property?
a. It cannot be magnetized. b. It is easy to magnetize. c. It is hard to magnetize. d. It attracts slowly moving charges.
An incompressible fluid is flowing through a vertical pipe with a constriction. The wide section is 2.00 cm in diameter and is at the top of the pipe. The pressure of the fluid in the wide section at the top is 200 kPa. The velocity of the fluid in the wide section is 4.00 m/s. The narrow section is located 2.00 m below the wide section. What is the diameter of the narrow section for the pressure of the fluid in the narrow section to equal the pressure in the wide section? (density of the fluid is 1,000 
A. 1.46 cm B. 1.20 cm C. 1.10 cm D. 0.90 cm E. 0.75 cm
For a certain metal, light of frequency 7.24 × 10-14 Hz is just barely able to dislodge photoelectrons from the metal. (h = 6.626 × 10-34 J ? s, 1 eV = 1.60 × 10-19 J, e = 1.60 × 10-19 C)
(a) What will be the stopping potential if light of frequency 8.75 × 10-14 Hz is shone on the metal? (b) What is the work function (in electron-volts) of this metal?
A wire carries a steady current of 0.1 A over a period of 200 s. What total charge passes through the wire in this time interval?
a. 2 C c. 0.005 C b. 200 C d. 20 C