AC circuits

In an AC circuit with a series combination of resistor and inductor, the phase angle between the current and the voltage is given by the formula:

• θ=tan−1(XL/R​​)

• θ=sin−1(XL/R​​)

• θ=cos−1(XL​/R​)

• θ=XL​/R​

What is the total impedance Z of a series R-L circuit with a resistor R=10 Ω and an inductor L=0.5 H when the frequency f=50 Hzf ?

• Z=10Ω

• Z=15Ω

• Z=12.5Ω

• Z=20Ω

In a purely capacitive AC circuit, what is the phase difference between the current and voltage?

• 0 degrees

• 45 degrees

• 90 degrees

• 180 degrees

In an R-C series circuit, if the resistor R=10 Ω and the capacitor C=10 μFC, what is the capacitive reactance at f=60 Hz?

• XC​=265.26Ω

• XC​=0.265Ω

• XC​=159.15Ω

• XC​=100Ω

A transformer has 400 turns in the primary coil and 100 turns in the secondary coil. If the primary voltage is 240 V, what is the secondary voltage?

• 60 V

• 120 V

• 480 V

• 100 V

The power factor of a purely inductive AC circuit is:

• 1/root of 2​

• 0

• 1

• -1

What is the formula for the average power P avg​ in a purely resistive AC circuit?

• Pavg​=Imax​*Vmax​

• Pavg​=IRMS*​VRMS​

• Pavg​=Vpeak*​Ipeak/2​​

• Pavg​=IRMS*​Vpeak​

In an R-L-C series circuit, if the total impedance is Z=50 Ω, the phase angle is 30 degree, and the supply voltage is V=220 V, what is the current in the circuit?

• I=4.4 A

• I=3 A

• I=2 A

• I=5 A

If the current in a series R-L circuit is given as I=5 A, the inductive reactance is XL=10 Ω, and the resistance is R=6 Ω, what is the voltage across the inductor?

• 50 V

• 30 V

• 60 V

• 70 V

What is the total reactance Xtotal of a circuit containing a capacitor of XC=15 Ω and an inductor of XL=10 Ω in series?

• Xtotal​=25Ω

• Xtotal​=5Ω

• Xtotal​=0Ω

• Xtotal​=100Ω