The frequency of a microwave signal is 9.76 GHz. What is its wavelength? (c = 3.00 × 108 m/s)
A) 3.07 cm
B) 2.07 cm
C) 1.07 cm
D) 5.07 cm
E) 4.07 cm
A
You might also like to view...
A comet entering the inner solar system from afar will
a. form a tail and some time later form a coma. b. form a coma and some time later form a tail c. always form a tail, but only sometimes form a coma
Brown dwarfs have
A) very narrow habitable zones B) no habitable zones C) very wide habitable zones D) habitable zones similar to the Sun
A copper wire, 0.8 mm OD, 5 cm long, is placed in an air stream whose temperature rises at a rate given by Tair = (10+ 14t)°C, where t is the time in seconds. If the initial temperature of the wire is 10°C, determine its temperature after 2 s, 10 s and 1 min. The heat transfer coefficient between the air and the wire is 40 W/(m2 K).
GIVEN
• A copper wire is placed in an air stream
• Wire diameter (D) = 0.8 mm=8*10-4 m
• Wire length (L) = 5 cm=0.05 m
• Air stream temperature is: Tair = (10 + 14t)°C
• The initial temperature of the wire (To) = 10°C
• The heat transfer coefficient ( )ch = 40 W/(m2 K)
FIND
• The wire temperature after 2 s, 10 s and 1 min
ASSUMPTIONS
• Constant and uniform heat transfer coefficient
SKETCH
PROPERTIES AND CONSTANTS
For copper at 127°C
• Thermal conductivity (k) = 383 W/(m K)
• Density (?) = 8933 kg/m3
• Specific heat (c) = 383 J/(kg K)
What are coronal holes?
What will be an ideal response?