The pupil of the eye controls:
A. the focal length of the eye
B. the far point
C. the near point
D. the amount of light reaching the retina
E. none of these.
D. the amount of light reaching the retina
You might also like to view...
Two radio antennas are 10 km apart on a north-south axis on high mountain tops at the seacoast
The antennas broadcast identical AM radio signals, in phase, at a frequency of 4.70 MHz. A steamship, 200 km offshore, travels toward the north at 15 km/h and passes east of the antennas. A radio on board the ship is tuned to the broadcast frequency. The reception of the radio signal on the ship is a maximum at a given instant. How much later until the next occurrence of maximum reception? (c = 3.00 × 108 m/s) A) 5.1 min B) 3.8 min C) 6.4 min D) 7.7 min E) 8.9 min
High-strength stainless steel is required for use in building structures and equipment (e.g. , cranes). It is produced by heat treating quench-hardened steel in a process called tempering that reduces brittleness and imparts toughness. In a production facility, alloy steel plates (k=50 W/(m K), c=460 J/(kg K) and ?=7865 kg/m3) of thickness 3 cm have to be tempered in a convective oven by heating them to 5500C. If the plates are initially at 400C and the air inside the heat treating oven is at 7000C with a convective heat transfer coefficient of 45 W/(m2 K), determine how long the plate has to remain in the oven.
GIVEN
• Alloy steel plate of thickness L=3 cm=0.03 m
• Tempering in oven to 5500C
• Initial temperature of the plate (To) = 40°C
• Heat treating oven temperature (T?) = 700°C
• Convective heat transfer coefficient ( ch ) = 45 W/(m2 K)
FIND
• The time required for the plate to reach 5500C.
ASSUMPTIONS
• Constant thermal conductivity
• End effects are negligible
SKETCH
The four fundamental forces in the Universe are the ___ forces
a. strong, weak, electrical, and magnetic b. electromagnetic, gravitational, nuclear, and weak c. electromagnetic, gravitational, strong, and weak d. magnetic, electroweak, gravitational, and strong e. electromagnetic, unified, strong, and weak
Answer the following statement(s) true (T) or false (F)
The Quantum Zeno effect shows that determining a quanton’s state often enough can prevent its evolution as predicted by the Time Evolution Rule.