The image produced by the lens of the eye on the retina when properly focused is:
A. real and inverted
B. virtual and inverted
C. real and upright
D. virtual and upright
A. real and inverted
You might also like to view...
If Q = 80 nC, a = 3.0 m, and b = 4.0 m in the figure, what is the magnitude of the electric field at point P?
a.
45 N/C
b.
70 N/C
c.
29 N/C
d.
47 N/C
e.
92 N/C
A net horizontal force is required for a body to move in a horizontal circle
Indicate whether the statement is true or false
Cooled air is flowing through a long sheet metal air conditioning duct, 0.2 m high and 0.3 m wide. If the duct temperature is 10°C and passes through a crawl space under a house at 30°C, estimate
(a) The heat transfer rate to the cooled air per meter length of duct.
(b) The additional air conditioning load if the duct is 20-m-long.
(c) Discuss qualitatively the energy conservation if the duct were insulated with glass
wool.
GIVEN
• An air conditioning duct in a crawl space
• Duct height (H) = 0.2 m
• Duct width (w) = 0.3 m
• Duct temperature (Ts) = 10°C
• Ambient temperature (T?) = 30°C
FIND
(a) The heat transfer rate per meter length (qc/L) to the cooled air in the duct
(b) The additional air conditioning load (q20) if the duct length (L) = 20 m
(c) Discuss qualitatively the energy conservation if the duct were insulated with glass wool
ASSUMPTIONS
• Ambient air is still
• Duct temperature is constant and uniform
• Radiation is negligible
• Edge effects are negligible
• No condensation on the duct surface
SKETCH
PROPERTIES AND CONSTANTS
for dry air at the mean temperature of 20°C
Thermal expansion coefficient (?) = 0.00341 1/K
Thermal conductivity (k) = 0.0251 W/(m K)
Kinematic viscosity (?) = 15.7 × 10–6 m2/s
Prandtl number (Pr) = 0.71
If the Moon is on the ecliptic, new, and at its farthest distance from Earth, we will get a(n) ________ eclipse
A) annual lunar B) total solar C) partial solar D) total lunar E) annular solar