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.
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.
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.
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.
39 exam-style questions on OCR A A Level Physics Oscillations, covering Simple harmonic oscillations, Energy of a simple harmonic oscillator, and Damping. Each one has a worked solution and a mark scheme showing where the marks go.