A light beam from a 2.1-mW He-Ne laser has a wavelength of 633 nm. How many photons does the laser emit in one second?
(h = 6.626 × 10-34 J ? s, c = 3.00 × 108 m/s)
A) 1.3 × 1016 B) 6.7 × 1015 C) 8.8 × 1015 D) 1.1 × 1016
B
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This figure shows idealized thermal radiation spectra from several stars and a human. Based on this graph, at about what wavelength does a 15,000 K star emit its most intense light?
A) about 100 nanometers B) about 1,000 nanometers C) about 20 nanometers D) about 100,000 nanometers
A steel plane truss is loaded at B and C by forces P 5 200 kN. The cross-sectional area of each member is A 5 3970 mm2. Truss dimen-sions are H 5 3 m and L 5 4 m. The maximum shear stress in bar AB is approximately:
(A) 27 MPa
(B) 33 MPa
(C) 50 MPa
(D) 69 MPa
Sound waves in air are transverse waves
Indicate whether the statement is true or false
Wiley Coyote has missed the elusive roadrunner once again. This time, he leaves the edge of the cliff at 50.0 m/s horizontal velocity. If the canyon is 100 m deep, how far from the edge of the cliff does the coyote land?