Estimate the ratio of the rate of stimulated to spontaneous emission at three wavelengths: (a) 12 cm, in the microwave (b) 5x10-4 cm, in the mid-infrared, and (c) 7x10-5 cm, in the ultraviolet. Assume a blackbody source (see Hollas p. 39) at 300 K. (d) Discuss the implications of the results determined in parts (a)-(c) for the following applications: fluorescence spectroscopy, excited state lifetime measurements (the lifetime of the excited state is inversely proportional to the Anm coefficient), and lasers (hint: what does it stand for

a solenoid is created by wrapping a l = 90 m long wire around a hollow tube of diameter d = 4.5 cm.   the wire diameter is d = 0.9 mm.   the solenoid wire is then connected to a power supply so that a current of i = 9 a flows through the wire.

randomized variablesl = 90 m

d = 4.5 cm

d = 0.9 mm

i = 9 a                                          

write an expression for the number of turns, n, in the solenoid. you do not need to take into account the diameter of the wire in this calculation.

calculate the number of turns, n, in the solenoid.

write an expression for the length of the solenoid (l2) in terms of the diameter of the hollow tube d.

calculate the length of the solenoid (l2)   in meters.

calculate the magnitude of the magnetic field at the center of the solenoid in teslas.

explanation:

igneous rocks also form where plates converge. the subducting plate melts as it sinks into the crust of the earth, and the melt rises into the overriding plate forming volcanoes. metamorphic rocks are formed mainly in the lithosphere, wherever there is high pressure and high temperature. -woods