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

Physics & Space Science

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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

Physics & Space Science

Sound waves in air are transverse waves

Indicate whether the statement is true or false

Physics & Space Science

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?

Physics & Space Science

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

Physics & Space Science