practice

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      [magnify]  
    When the Apollo astronauts landed on the moon they left behind equipment to monitor such things as the moon's internal temperature, its magnetic and gravitational fields, seismic activity caused by moonquakes and meteor impacts, and the moon's extremely thin atmosphere. Known collectively as the ALSEP (an acronym for Apollo Lunar Surface Experiment Packages) these devices were powered by a small and very simple nuclear power plant called a SNAP (an acronym for Space Nuclear Auxiliary Power). A SNAP generator is basically a can of plutonium 238 dioxide surrounded by radiator fins with thermocouples in between. The difference in temperature between the decaying plutonium (600 °C) and the the radiator fins (275 °C) produces a voltage across the thermocouples that can be used to generate electric current. The whole contraption is about the size of an office watebasket and with no moving parts is reliable for very long periods of time.

    The SNAP-27 activated by the Apollo XIV crew on 5 February 1971 used 3.8 kg of plutonium 238 dioxide and generated 73 W of power when first turned on. If 238PuO2 has a half life of 87.74 years and decays via the emission of 5.593 MeV alpha particles, determine …
    1. the initial power radiated by the plutonium fuel
    2. the initial efficiency of the generator
    3. the power of the generator on the anniversary of the Apollo XIV mission from the day it was turned on until its centennial.
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conceptual

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numerical

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algebraic

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calculus

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statistical

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investigative

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worksheets

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