13. In Figure, observer S detects two flashes of light. A big flash occurs at x₁ = 1200 m and, 5.00 μs later, a small flash occurs at x₂ = 480 m. As detected by observer S', the two flashes occur at a single coordinate x'. (a) What is the speed parameter of S', and (b) is S' moving in the positive or negative direction of the x axis? To S', (c) which flash occurs first and (d) what is the time interval between the flashes? (15分)

12. A High-Pass Filter. One application of L-R-C series circuits is to high-pass or lowpass filters, which filter out either the low- or high-frequency components of a signal. A highness filter is shown in Figure, where the output voltage is taken across the L-R combination. (a) Derive an expression for (Vout / Vs), the ratio of the output and source voltage amplitudes, as a function of the angular frequency ω of the source and R, L, and C parameters. (b) Show that when ω is small, this ratio is proportional to ω and thus is small, and (c) show that the ratio approaches unity in the limit of large frequency. [15分, find the reactance of L and C to construct the voltage and current]

相關申論題

相關試卷