31. Alternating Current

Show that the quantity ϵ₀(dΦ_e/dt) has units of current.

A capacitor has a peak current of 330 μA when the peak voltage at 250 kHz is 2.2 V. If the peak voltage is held constant, what is the peak current at 500 kHz?

An AC source operates at a maximum voltage of 120 V and a frequency of 60 Hz. If it is connected to a 175 µF capacitor, what is the maximum charge stored on the capacitor?

What are V_R and V_C if the emf frequency in FIGURE EX32.19 is 2.5 kHz?

For an RC circuit, find an expression for the angular frequency at which V_R = ½ ε₀.

Suppose an air-gap capacitor has circular plates of radius r = 2.5 cm and separation d = 1.6 mm. A 68.0-Hz emf, ε = ε₀ cos ωt, is applied to the capacitor. The maximum displacement current is 35 μA. Determine the maximum value of dΦE/dt between the plates. Neglect fringing.

A 20 nF capacitor is connected across an AC generator that produces a peak voltage of 5.0 V. At what frequency f is the peak current 50 mA?

What is the peak voltage across the 3.0 μF capacitor?

Suppose an air-gap capacitor has circular plates of radius r = 2.5 cm and separation d = 1.6 mm. A 68.0-Hz emf, ε = ε₀ cos ωt, is applied to the capacitor. The maximum displacement current is 35 μA. Determine the value of ε₀. Neglect fringing.