1. The standard electric voltage in a 60-Hz alternating-current circuit is given by V = 170 sin 120 πt, where t is the time in seconds. Sketch two periods of the graph of V as a function of t. Give amplitude and period of the function.
2. The electric current i (in μA) in a electric circuit is given by i = 4.8 cos 2 π (t + 0.4), where t is the time in seconds. Sketch three cycles of this function. Give amplitude, period and displacement for the function.
3. A particular AC circuit has a resistor of 4 Ω, a reactance across an inductor of 8 Ω and a reactance across a capacitor of 11 Ω.
a. Represent the impedance by a complex number, in rectangular form and in polar form.
b. Find the magnitude of the impedance and its phase angle.
c. Does the voltage lead or lag the current? Explain.