Physics, 02.12.2021 22:30 ohnoitsabby5431
A sodium vapor lamp (λ ~ 6 ´ 10-7 m) radiates 100 w of output uniformly in all directions. At what distance from the lamp will the photons have an average density of 106 m-3 ?.
Answers: 2
Physics, 21.06.2019 21:00
Amarble, a bowling ball, a basketball, and a baseball are rolling across the floor at 10 m/s. which one has the greatest kinetic energy? the marble the bowling ball the basketball the baseball
Answers: 1
Physics, 22.06.2019 08:00
Aheat engine running backward is called a refrigerator if its purpose is to extract heat from a cold reservoir. the same engine running backward is called a heat pump if its purpose is to exhaust warm air into the hot reservoir. heat pumps are widely used for home heating. you can think of a heat pump as a refrigerator that is cooling the already cold outdoors and, with its exhaust heat qh, warming the indoors. perhaps this seems a little silly, but consider the following. electricity can be directly used to heat a home by passing an electric current through a heating coil. this is a direct, 100% conversion of work to heat. that is, 19.0 \rm kw of electric power (generated by doing work at the rate 19.0 kj/s at the power plant) produces heat energy inside the home at a rate of 19.0 kj/s. suppose that the neighbor's home has a heat pump with a coefficient of performance of 4.00, a realistic value. note: with a refrigerator, "what you get" is heat removed. but with a heat pump, "what you get" is heat delivered. so the coefficient of performance of a heat pump is k=qh/win. an average price for electricity is about 40 mj per dollar. a furnace or heat pump will run typically 200 hours per month during the winter. what does one month's heating cost in the home with a 16.0 kw electric heater? what does one month's heating cost in the home of a neighbor who uses a heat pump to provide the same amount of heating?
Answers: 2
Physics, 23.06.2019 00:30
Which of the following is a true statement about the acceleration ~a of the pendulum bob ~a is equal to the acceleration due to gravity. ~a is perpendicular to the bob’s trajectory. ~a is equal to the instantaneous rate of change in velocity. ~a is tangent to the bob’s trajectory.
Answers: 1
A sodium vapor lamp (λ ~ 6 ´ 10-7 m) radiates 100 w of output uniformly in all directions. At what d...
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