The very first living organisms on the Earth were probably
A) chemoheterotrophs
B) photoautotrophs
C) photoheterotrophs
D) chemoautotrophs
D
You might also like to view...
A 2.5-cm-OD hot steam line at 100°C runs parallel to a 5.0-cm-OD cold water line at 15°C. The pipes are 5 cm center to center and deeply buried in concrete with a thermal conductivity of 0.87 W/(m K). What is the heat transfer per meter of pipe between the two pipes?
GIVEN
Hot pipe outside diameter (Dh) = 2.5 cm = 0.025 m
Hot pipe temperature (Th) = 100°C
Cold pipe outside diameter (Dc) = 5.0 cm = 0.05 m
Cold pipe temperature (Tc) = 15°C
Center to center distance between pipes (l) = 5 cm = 0.05 m
Thermal conductivity of concrete (k) = 0.87 W/(m K)
FIND
The heat transfer per meter of pipe (q/L)
ASSUMPTIONS
Two dimensional heat transfer between the pipes
Steady state conditions
Uniform thermal conductivity
SKETCH
The heating element of a toaster is a 5.4-m length of nichrome wire of diameter 0.48 mm. The resistivity of nichrome at the operating temperature of the toaster is 1.3 × 10-6 ? ? m
The toaster is designed to operate at a voltage of 120 V. How much power does it draw in normal operation? A) 370 W B) 360 W C) 380 W D) 400 W E) 410 W
Which of the following kinds of stars is most dense?
a. a supergiant star b. a main sequence star c. a giant star d. a white dwarf e. the sun
Fig. 10-3 illustrates a simplified roller bearing. The outer hollow cylinder has a radius of 1.20 cm and is stationary. The inner cylinder has a radius of 1.00 cm and is rotating at 9.00 rpm
Between the two cylinders are several small cylinders with a radius of 0.100 cm, which roll without slipping on both the inner and outer cylinders. Only one of these cylinders is shown in the figure. How long does it take a small cylinder to complete a full revolution around the inner cylinder? A) 6.00 s B) 14.7 s C) 5.64 s D) 0.542 s E) 1.38 s