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Oscillations

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12
Question 1

An alternating current with a microwave frequency of f=12 GHzf = 12\text{ GHz}f=12 GHz is transmitted through a signal cable. Inside a metallic core of this cable, the peak alternating current is 48 mA48\text{ mA}48 mA. The core has a cross-sectional area of 1.2×10−8 m21.2 \times 10^{-8}\text{ m}^21.2×10−8 m2 and a free electron number density of 5.0×1028 m−35.0 \times 10^{28}\text{ m}^{-3}5.0×1028 m−3.

a.

Show that the maximum drift velocity of each conduction electron in the core is 5.0×10−4 m s−15.0 \times 10^{-4}\text{ m s}^{-1}5.0×10−4 m s−1.

[3]
b.

The motion of these conduction electrons is modeled as simple harmonic motion. Use the drift velocity from (i) to calculate the amplitude AAA of this oscillation.

[3]
c.

Without further calculation, explain how the maximum acceleration of a conduction electron varies as the frequency fff of the alternating current is adjusted, provided that the peak alternating current remains constant.

[3]

Oscillations Questions

  1. A Level
  2. /Physics
  3. /Oscillations