Camera Exposure: A zoom lens for a camera is adjusted to change its focal length from 38 mm to 304 mm. If the same amount of light is to be admitted to the lens in both cases, what is the final f-number if the original f-number was f/2.0?
Fill in the blank(s) with the appropriate word(s).
f/16
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The water in a river flows downstream at 3.0 M/s. A boat is motoring upstream against the flow at 5.0 m/s. What is the boats speed of relativity to the riverbank/
A. 8.0 M/s B. 5.0 M/s C. 3.0 M/s D. 2.0 m/s
Most of the deuterium that formed right after the Big Bang:
A) is still around today. B) broke down into electrons and neutrons. C) turned into dark matter. D) quickly burned into helium nuclei. E) was found in the globular clusters.
The figure below shows a planet traveling in a counterclockwise direction on an elliptical path around a star located at one focus of the ellipse. When the planet is at point A,
A. its speed is constant. B. its speed is increasing. C. its speed is decreasing. D. its speed is a maximum. E. its speed is a minimum.
What is the mean free path for the molecules in an ideal gas when the pressure is 100 kPa and the temperature is 300 K given
that the collision cross-section for the molecules of that gas is 2.0 × 10-20 m2? Boltzmann's constant is k = 1.38 × 10-23 J/K. A) 1.1 × 10-6 m B) 2.1 × 10-6 m C) 1.7 × 10-6 m D) 5.3 × 10-6 m E) 1.5 × 10-6 m