RLC circuits

Which of the transposed reactance formulae is incorrect?

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Select the correct phrase:

• In a capacitive circuit the voltage leads the current.

• In an inductive circuit the current lags the voltage.

• In a resistive circuit, the current and voltage are out of phase.

• In a capacitive circuit the current lags the voltage.

Select the correct sentence:

• Active power can only be developed in a pure inductance.

• Reactive power is developed in a capacitor.

• Apparent power increases as the power factor increases.

• Power factor is apparent power divided by active power.

Select the correct combination of quantity (equation) symbol and unit:

• W, Watt

• P, VAr

• X, Ohm

• Q, Watt

In a sinusoidal AC circuit containing an inductance and a resistance in series:

• the sum of the voltages across both components, as measured by a multimeter, adds up to the supply voltage.

• the voltage across both components are out of phase by 90 degrees.

• the current through each component is different.

• the inductance is proportional to the supply frequency.

Complete the sentence:

In a parallel circuit containing a capacitor and resistor connected to a sinusoidal supply:

• the voltage across each component is the same.

• the current in each component is the same.

• the current in the capacitor lags the applied voltage by 90 degrees.

• the total current drawn goes down as the frequency goes up.

Suppose an RLC series circuit like the one shown has (R = 91.0 Ω, C = 6.00 μF, and L = 60.0 mH) .
The source of time-varying emf has an angular frequency of (ω = 64.0 rad/s) .
1- What is the impedance of this circuit?
 $Z=\ \sqrt{R^2+\left(X_L-X_C\right)^2}\$  ,  $X_L=\omega L\ \ \ ,\ X_C=\frac{1}{\omega C}$  

•  $2.60\ x\ 10^3\ \Omega$  

•  $6.77\ x\ 10^6\Omega$  

• 51.0  $\Omega$  

When applying a fixed voltage AC at different frequencies through a capacitor with a capacitance of C as in the opposite figure, which of the following illustrates the relationship between current and frequency?

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A circuit contains a source of time-varying emf, which is given by Vemf = 120.0 sin[(377 rad/s)t] V, and a capacitor with capacitance C = 5.00 μF. What is the current in the circuit at t = 1.00 s?
 $I_c=\omega CV_c\sin\left(\omega t+\frac{\pi}{2}\right)$  

• 0.226 A

• 0.451 A

• 0.555 A

• 0.750 A

The phase constant, ϕ, between the voltage and the current in an AC circuit depends on the _______.

• a) inductive reactance

• b) capacitive reactance

• c) resistance

• d) all of the above