Which of these is not involved in the operation of lasers?
a. stimulated emission c. metastable state
b. population inversion d. blackbody radiation
D
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Water is to be condensed at 1 atmosphere pressure in a compact heat exchanger having vertical stainless steel plates at 40ºC. Plot the condensation boundary layer thickness flowing down the vertical surface as a function of the distance down the plate, assuming laminar flow. At what point would you assume the condensate flow to become turbulent?
What will be an ideal response?
Wave Characteristics: A radio station broadcasts at a frequency of 80 MHz. How far from the transmitter will this signal travel in 67 ms? (c = 3.0 × 108 m/s)
A. 60 × 106 m B. 67 m C. 40 km D. 80 km E. 20 × 106 m
An object attached to an ideal massless spring is pulled across a frictionless surface. If the spring constant is 45 N/m and the spring is stretched by 0.88 m when the object is accelerating at what is the mass of the object?
A) 20 kg B) 17 kg C) 22 kg D) 26 kg
A billiard ball collides in an elastic head-on collision with a second stationary identical ball. After the collision which of the following conditions applies to the first ball?
a. maintains the same velocity as before c. comes to rest b. has one-half its initial velocity d. moves in the opposite direction