LU 6 Alternating Current (6.3)

In pure resistor circuit, the current is...

• leads the voltage by π/2 rad

• out of phase with voltage

• lags behind the voltage by π/2 rad

• in phase with the voltage

How does a capacitor react to AC?

• As the frequency increases, the reactance decreases

• As the frequency increases, the reactance increases

• As the amplitude increases, the reactance increases

• As the amplitude increases, the reactance decreases

In a pure capacitor circuit, what is the relationship of voltage and current?

• I leads V by π/2 rad

• I and V are in phase

• V leads I by π/2 rad

• I and V are in phase shift

Which of the following statements CORRECTLY shows the effect on X_L when f is increased to 2f ?

• X_L increases by a factor of two

• X_L decreases by a factor of two

• X_L increases by a factor of four

• X_L decreases by a factor of four

Which of the following statements is CORRECT about pure inductor circuit?

• I leads V by π/2 rad

• I leads V by π rad

• V leads I by π/2 rad

• V leads I by π rad

The current in RCL circuit is maximum when the frequency is...

• f = 2πLC

• f = 1 / 2πLC

• f = √2πLC

• f = 1 / 2π√LC

What is the condition for RCL circuit to oscillate at resonant frequency?

• R & X_C must be equal

• R & X_L must be equal

• X_C & X_L must be equal

• R, X_C & X_L must be equal

What is the total opposition of current flow in AC circuit?

• Capacitance reactance

• Resistance

• Inductive reactance

• Impedance