Astronomy's largest optical telescopes are ________.
A. refractors
B. diffractors
C. deflectors
D. reflectors
Answer: D
You might also like to view...
Viscosity: Motor oil, with a viscosity of 0.25 N ? s/m2, is flowing through a tube that has a radius of 5.0 mm and is 25 cm long. The drop in pressure is 300 kPa. What is the volume of oil flowing through the tube per second?
A. 0.00038 m3/s B. 0.025 m3/s C. 0.0012 m3/s D. 4.7 m3/s E. 7.5 m3/s
Suppose two flat glass plates 30-cm long are in contact along one end and separated by a human hair at the other end. If the diameter of the hair is 50 ?m, find the separation of the interference fringes when the plates are illuminated by green light, ? = 546 nm.
What will be an ideal response?
A straight wire is bent into the shape shown. Determine the net magnetic force on the wire when the current I travels in the direction shown in the magnetic field 
.
A. 2IBL in the ?z direction B. 2IBL in the +z direction C. 4IBL in the +z direction D. 4IBL in the ?z direction E. zero
How many radioactive atoms are present in a sample that has an activity of 0.5 mCi and a half-life of 10 years? (1 curie = 3.7 × 10^10 decays/s)
a. 9.5 × 10^12 atoms b. 8.4 × 10^12 atoms c. 7.3 × 10^12 atoms d. 6.5 × 10^12 atoms e. 2.7 × 10^5 atoms