What is the intensity level in decibels of a sound with intensity 10-3 W/m2? The threshold of human hearing is 1.0 × 10-12 W/m2
A) 30 dB
B) 60 dB
C) 90 dB
D) 96 dB
C
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When a person with a near point at 28 cm uses a certain magnifying glass, it produces an angular magnification of 7.0 with the image very distant. What is the focal length of the lens of this magnifying glass?
A) 2.0 cm B) 3.0 cm C) 4.0 cm D) 5.0 cm E) 6.0 cm
The ordered structure NiAl has been investigated as a high-temperature gas-turbine material; however, brittle fracture is a problem with this alloy. Theoretical calculations have determined that the enthalpy of the ordered NiAl structure is 0.15 eV per atom less than for a disordered structure. The NiAl ordered structure is a cube with Ni at 0,0,0 and Al at 1/2,1/2,1/2.
(a) What is the Bravais lattice type for NiAl? (b) What is the GFE change if this alloy disorders at 1900 K? (c) Based upon your result for (b), predict if NiAl is ordered or disordered at 1900 K. (d) From the Ni-Al phase diagram in Figure 5.15, to what temperature does the NiAl phase remain ordered?
The lowest A on a piano has a frequency of 27.5 Hz. If the tension in the 2.0-m long string is 151 N and one-half wavelength occupies the string, what is the mass of the string?
a. 100 g c. 37 g b. 25 g d. 50 g
The voltage supplied to an ac circuit is given by v = 120 sin(377t). What is the voltage at 
A. 0.00 V B. 2.37 V C. 63.0 V D. 109 V E. 119 V