What is the phase relationship between the current I and the applied voltage V in an R-L series circuit?

• I is independent of V

• I leads V

• I lags V

• I is in phase with V

In the phasor diagram of an R-L circuit, which voltage is in phase with the current?

• V

• VR

• VC

• VL

What is the formula for calculating the phase angle Φ in an R-L circuit?

• Φ = R/XL

• Φ = tan⁻¹(XL/R)

• Φ = XL/R

• Φ = tan⁻¹(R/XL)

What does the quantity Z represent in an R-L circuit?

• Complex impedance

• Inductive reactance

• Resistance

• Power factor

What is the unit of admittance in an A.C. circuit?

• Volt

• Ampere

• Siemen

• Ohm

In an R-C series circuit, which voltage lags behind the current?

• VL

• VR

• V

• VC

What happens to the power factor when the circuit is purely resistive?

• It becomes infinite

• It becomes unity

• It becomes negative

• It becomes zero

If the applied voltage is v(t) = Vm sin(ωt), what is the equation for the circuit current in an R-L circuit?

• i = Im sin(ωt)

• i = Im sin(ωt - Φ)

• i = Im cos(ωt - Φ)

• i = Im sin(ωt + Φ)

What is the effect of increasing the inductive reactance XL in an R-L circuit?

• Voltage decreases

• Phase angle decreases

• Current increases

• Phase angle increases

In the context of power in an R-L circuit, what does the term cos Φ represent?

• Current

• Voltage

• Impedance

• Power factor