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WorksheetsUNIT-2: AC CIRCUITS (MCQs)
Total questions: 31
Worksheet time: 16mins
The earthing system observed in the power plant ensures:
Stabilization of the control system
Safety — prevents shock & equipment damage
Extra current storage
High voltage generation
The cables used for power distribution in the plant were mostly:
Thin signal wires
High-voltage armored cables
Plastic fiber cables
Telephone cables
Instantaneous power in an AC circuit is given by:
P = VI
p(t) = v(t) × i(t)
Pavg = VI cosΦ
P = I²R
Active power is also called:
Real power
Reactive power
Complex power
Apparent power
The Diesel Generator (DG) set switches on automatically when:
Campus load increases
Temperature increases
Grid power fails
Voltage becomes low
Apparent power is measured in:
Watt
VAR
VA
Coulomb
Power backup for critical medical equipment at Amrita Hospital is ensured by:
Solar cells only
UPS + Battery bank + DG sets
Water turbines
None
Transformers seen in the power plant are mainly used for:
Power factor correction
Stepping up or stepping down voltage
Storing electrical energy
Generating harmonic signals
Phasors represent:
Time-varying DC levels
AC signals as rotating vectors
The average value of voltage
Only resistive signals
In a purely capacitive circuit, the current:
Lags voltage by 90°
Leads voltage by 90°
A state variable is:
Any variable that expresses output
A variable that defines the internal condition of system
Any external input variable
None of these
State space representation is used for:
Only first-order systems
Only frequency domain
Multi-input multi-output (MIMO) systems
Only mechanical systems
DHBVN primarily supplies electricity to which major areas?
Gurgaon, Faridabad, Hisar, Sirsa
Delhi, Noida, Ghaziabad
Jaipur, Udaipur, Kota
Faridabad
The canonical state-space model of a series RLC circuit will consist of:
One state variable
Two state variables
Three state variables
No state variables
In a state model, matrix B represents:
Output constants
Relation between state and input
Relation between output and state
Feedback constants
In an inductive circuit, reactive power is:
Positive
Negative
Zero
Infinite
The vector sum of active and reactive power gives:
Apparent power
Real power
Instantaneous power
Power factor
If voltage = Vmax sin(ωt), current = Imax sin(ωt – 90º), the circuit is:
Purely resistive
Purely inductive
Purely capacitive
Resonant
A phasor diagram represents sinusoidal signals in terms of:
Magnitude only
Phase only
Magnitude and phase
Time
Power factor is zero for:
Resistive circuit
Inductive circuit
Capacitive circuit
Both b and c (pure reactances)
A state model consists of:
Only input equation
Only output equation
Both state and output equations
No equation
In state space, the output equation is:
y = Ax + Bu
y = Cx + Du
y = Dx + Cu
y = (Ax + Bu)C
The R in RLC circuit contributes:
Energy storage
Energy dissipation
Energy generation
Phase shift only
The number of state variables for an nth order system is:
1
n
n²
2n
The capacitor voltage in an RLC state-space model is usually taken as:
(a)
Which of the following is a state variable?
Output variable
Output variable
State variable
Impedance
In a drone flight controller, the state variables are MOST likely:
Battery voltage and LED brightness
Altitude, pitch angle, roll angle, yaw rate
Wi-Fi strength and GPS time
Propeller color and size
A heart-rate control system in a medical ventilator uses state-space variables to:
Track doctor movement
Monitor patient’s voice
Estimate rate and oxygen pressure levels
Control lights inside ICU
The state variables in a system represent:
The future output of the system
The past values of input
The minimum set of variables that describe the system’s state at any time
The Laplace representation of the system
A second-order RLC series circuit has L, R, C. If state variables are chosen as x1=i(t) (current), x2=vC(t) (capacitor voltage), then the number of state equations is:
1
2
3
Depends on input
Which of the following is correct?
Value of input u(t)
Eigenvalues of matrix A
Dimension of matrix B
Feedback gain only
