Exam 31: Electromagnetic Oscillations and Alternating Current

An ac generator producing 10 V (rms)at 200 rad/s is connected in series with a 50- $\Omega$ resistor, a 400-mH inductor, and a 200- $\mu$ F capacitor.The rms voltage across the capacitor is:

A 35- $\mu$ F capacitor is connected to an ac source of emf with a frequency of 250 Hz and a maximum emf of 20 V.If the voltage across the capacitor is zero at time t = 0, what is the voltage at time t = 3.0 ms? Assume the phase constant is zero.

A series circuit consists of a 15- $\Omega$ resistor, a 25-mH inductor, and a 35- $\mu$ F capacitor.If the frequency is 100 Hz the power factor is:

An LC circuit has an inductance of 15 mH and a capacitance of 10 $\mu$ F.At one instant the charge on the capacitor is 25 $\mu$ C.At that instant the current is changing at the rate:

In the diagram, the function y(t)= y_msin( $\omega$ t)is plotted as a solid curve.The other three curves have the form y(t)= y_msin( $\omega$ t + $\phi$ ), where $\phi$ is between - $\pi$ /2 and + $\pi$ /2.Rank the curves according to the value of $\phi$ , from the most negative to the most positive.

An RLC series circuit, connected to a source , is at resonance.Then: