Physics
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A pure germanium crystal has a resistivity of 0.60 Ω•m and 2.5 × 1013 electrons/cm3 at 20 °C. a) Determine the mean free time for germanium at this temperature. b) Determine the mean free time for germanium when it is greater than the mean free time for some other type of conducting material. Provide a reason for why there is a high resistivity for germanium relative to a conductor.
In a silicon semiconductor, electrons have an average collision time of 40 ns. An electron takes 3.4 × 103 minutes to travel 2.0 m within the semiconductor. Find the number of collisions the electron makes with ions over this distance.
Consider two wires A and B, in which the number of electrons flowing per unit of time is the same. The wires are identical in terms of material, but the diameter of wire A is 0.8 cm, and of wire B is 1.6 cm. If in wire A electron drift speed is 3.2 × 10-4 m/s, find the electron drift speed in wire B.
A 1.8 mm diameter copper wire carries a current of 8.0 A. Determine the magnitude of the electric field required to produce this current in the wire. The conductivity (σ) of copper at room temperature is 5.96 × 10 7 (Ω·m) -1.
Consider a copper wire segmented into two different sections, labeled 1 and 2. Both sections, although of different diameters, carry the same constant current of 8.0 A. Determine the drift velocity of the electron in each section. The number density of electrons in copper is 8.5 × 1028 m-3.
Find the time required for two moles of electrons to pass through a cross-section of a 1.4 mm diameter silver wire, given that the electron drift speed within the wire is 4.2 × 10-4 m/s. The number density of electrons in silver is 5.86 × 1028 m-3.
Determine the drift speed of the electron, given that 2.1 × 1019 electrons pass through a cross-section of a 1.4 mm diameter copper wire in 12s. The number density of electrons in copper is 8.5 × 1028 m-3.
The electrons in a semiconductor have an average time between collisions of 7.0 ps. Given an electron moves at a drift speed of 3.5 × 10-3 m/s in the semiconductor, determine the magnitude of the electric field.
In a silver wire, the average time interval between collisions for electrons is 12ps. If the intensity of the electric field is 42 mV/m, determine the speed at which the electron drift.