The density of mobile electrons in copper metal is 8.4 x 1028 m . Suppose that i = 5.6 x 1018 electrons/s are drifting through a copper wire. (This is a typical value for a simple circuit.) The diameter of the wire is 0.6 mm. In this case, about how many minutes would it take for a single electron in the electron sea to drift from one end to the other end of a wire 29 cm long? minutes (A puzzle: if the drift speed is so slow, how can a lamp light up as soon as you turn it on?

Which magnetic property best describes a magnet’s ability to act at a distance? magnets are dipolar. magnets attract only certain objects. magnets have magnetic fields. magnets can transfer their properties to certain materials.

Consider a file currently consisting of 200 blocks. assume that the file control block (and the index block in the case of indexed allocation) is already in memory. calculate how many disk i/o operations are required for contiguous, linked, and indexed (single-level) allocation strategies, for each of the conditions listed below. in the contiguous-allocation case, assume that there is not room to grow at the beginning but there is room to grow at the end. also assume that the block information to be added is stored in memory.

Ais a machine that makes work easier when a single force is applied. a simple machine b compound machine c endangered machine d complex machine