Alternating Current

What is the main reason a choke coil is not used in dc circuits?

Because the resistance of the coil is very high
Because XL is infinite
Because XL is zero (correct)
Because the inductance is very small

What is the condition for resonance in a series RLC circuit?

When XL = XC (correct)
When XC = R
When XL = XC = R
When XL = R

A series RLC circuit has a resistance of 300 Ω, an inductance of 0.9 H, and a capacitance of 2.0 μF. What is the impedance of the circuit if the angular frequency is 1000 rad/s?

500 Ω (correct)
400 Ω
900 Ω
1300 Ω

In a series RLC circuit, what is the relationship between the voltage across the resistor, inductor, and capacitor?

VL + VC + VR = 0 (D) Signup and view all the answers

What is the relationship between the elements in an RC circuit?

tanφ = XC (B) Signup and view all the answers

In a series RLC circuit, what is the condition for resonance?

XL = XC (D) Signup and view all the answers

What is the phase angle φ in an RC circuit?

π/4 (D) Signup and view all the answers

What is the impedance of a circuit with R = 1kΩ, L = 10H, and C = 10μF?

R + (XL - XC) (A) Signup and view all the answers

What is the equation of voltage in a series RLC circuit?

V = VR^2 + (VL - VC)^2 (C) Signup and view all the answers

What is the phase angle between the voltage and current in a purely resistive circuit?

0o (C) Signup and view all the answers

What is the formula for the impedance of an RLC circuit?

Z = sqrt(R^2 + XC^2) (C) Signup and view all the answers

What is the condition for resonance to occur in an LC circuit?

XL = XC (D) Signup and view all the answers

What is the phase angle between the voltage and current in a purely inductive circuit?

90o (C) Signup and view all the answers

What is the formula for the RMS value of an AC voltage source?

Vrms = V0 / sqrt(2) (C) Signup and view all the answers

What is the reciprocal of resistance?

Conductance (D) Signup and view all the answers

Why can't dc meters be used to measure ac?

Because the average value of ac current is zero (B) Signup and view all the answers

What is the unit of impedance?

Ohm (A) Signup and view all the answers

What type of reactance is offered by a capacitor?

Capacitive reactance (A) Signup and view all the answers

What is the relationship between XL and XC in an LC circuit?

XL = XC (C) Signup and view all the answers

In the given circuit, what is the value of the total impedance if the frequency of the AC source is 50 Hz?

8.66 Ω (C) Signup and view all the answers

What is the reading of the ammeter in the given circuit if the AC source has a voltage of 20 cos(2000t) and the circuit has a resistance of 4 Ω, an inductance of 5 mH, and a capacitance of 50 μF?

0.47 A (D) Signup and view all the answers

In the given circuit, what is the value of the inductance if the current is maximum at a frequency of 50 Hz and the capacitance is 10 μF?

50 π Henry (A) Signup and view all the answers

What is the relationship between the voltage across the inductor and the capacitor in the given circuit when it is at resonance?

VL = VC (D) Signup and view all the answers

What is the value of the self-inductance of a choke coil if it is given as 10 mH?

0.01 H (A) Signup and view all the answers

What is the relationship between the r.m.s value of an AC voltage and the peak value?

The r.m.s value is the peak value divided by the square root of 2 (C) Signup and view all the answers

What is the average value of an alternating current over one complete cycle?

It is zero (B) Signup and view all the answers

What is the formula for the r.m.s value of a complex AC current wave?

$i_{rms} = \$a^2 + b^2\$ (C) Signup and view all the answers

What is the average value of an AC voltage over half a cycle?

It is 63.7% of the peak value (D) Signup and view all the answers

What is the relationship between the r.m.s value of an AC voltage and the value of a DC voltage that produces the same heating effect?

The r.m.s value is equal to the DC voltage (A) Signup and view all the answers