A helium-neon laser emits red light having a wavelength of 6.4 × 10^-7 m and a power of 0.5 mW. How many photons are emitted each second?
a. 6.4 × 10^38
b. 1.6 × 10^21
c. 3.2 × 10^25
d. 2.6 × 10^18
e. 1.6 × 10^15
E
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The most important property that determines the evolution of a star is its
A. composition. B. mass. C. temperature. D. location.
In a two-object inelastic collision, how are the final velocities of the objects related?
A. There is no relation. B. The larger mass has the larger velocity. C. The larger mass has the smaller velocity. D. They each have the same velocity.
Fluid Flow: Water flows through a horizontal pipe of cross-sectional area 10.0 cm2 at a pressure of 0.250 atm with a flow rate is 1.00 L/s. At a valve, the effective cross-sectional area of the pipe is reduced to 5.00 cm2. What is the pressure at the valve? The density of water is 1000 kg/m3, and treat it as an ideal incompressible fluid.
A. 0.110 atm B. 0.235 atm C. 0.200 atm D. 0.157 atm E. 7700 Pa
An atomizer works because of Bernoulli's principle
a. True b. False Indicate whether the statement is true or false