Incandescent Bulb. Incandescent light bulbs work by electrically heating a metallic filament to a high temperature so that it emits thermal radiation in the visible range. Assume a 50 W incandescent bulb uses a tungsten filament with a diameter of 0.2 mm and a length of 30 mm (ignore emission from the ends of the filament), the consumed electrical power (50 W) is all radiated out by the filament, and the filament can be modeled as a blackbody. (a) What is the temperature of the filament when the bulb works at 50 W? (b) What is the wavelength of radiation with the highest emissive power? (c) The radiation with wavelength between 400 nm and 700 nm is visible and thus is the "useful" output from the light bulb. The ratio of emitted power within this wavelength range to the total emitted power is defined as the efficiency of the bulb. Calculate the efficiency of the incandescent bulb in this case. What is the "efficiency" of the sun by this definition?
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Physics, 21.06.2019 14:40
An implanted pacemaker supplies the heart with 72 pulses per minute, each pulse providing 6.0 v for 0.65 ms. the resistance of the heart muscle between the pacemaker’s electrodes is 550 ω. find (a) the current that flows during a pulse, (b) the energy delivered in one pulse, and (c) the average power supplied by the pacemaker.
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Physics, 22.06.2019 00:30
Asap time is ! best answer gets compose at least one well-developed paragraph on the following: define the term concurrent powers, and give an example of a concurrent power of government.
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Physics, 22.06.2019 23:00
Astronomers studying the planet of rhombus have detected sedimentary rock on its surface. one astronomer wonders if material in this sedimentary rock used to be in igneous rock deep in rhombus’s interior. can igneous rock become sedimentary rock? explain your answer.
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Physics, 23.06.2019 00:10
An electromagnetic wave with frequency 65.0 hz travels in aninsulating magnetic material that has dielectric constant 3.64 andrelative permeability 5.18 at this frequency. the electric fieldhas amplitude 7.20 \times 10^{ - 3} {\rm v}/{\rm m}. a. what is the speed of propagation of the wave? b.what is the wavelength of the wave? c.what is the amplitude of the magnetic field? d.what is the intensity of the wave?
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Incandescent Bulb. Incandescent light bulbs work by electrically heating a metallic filament to a hi...
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