Ohm’s law defines the relationship between voltage, current, and resistance in a circuit. It states that the voltage across a resistor is directly proportional to the current through it, with resistance being the constant of proportionality.
What is the total resistance in a series circuit?
A Minimum resistance
B Average resistance
C Maximum resistance
D Sum of resistances
In a series circuit, the total resistance is the sum of the individual resistances. This means that adding more resistors in series increases the total resistance of the circuit.
In a parallel circuit, how is current divided?
A According to resistance
B At random
C Equally
D Based on voltage
In a parallel circuit, the current is divided among the branches based on their respective resistances. The branch with lower resistance will carry more current than the branch with higher resistance.
What does a capacitor store?
A Thermal energy
B Light energy
C Electric energy
D Magnetic energy
A capacitor stores energy in the form of an electric field. It does so by accumulating positive charge on one plate and negative charge on the other, releasing this energy when needed in the circuit.
What is the main function of an inductor?
A Store energy
B Resist current change
C Increase current flow
D Generate voltage
Inductors resist changes in the current flowing through them. They store energy in a magnetic field when current passes through, opposing any sudden changes in the current flow.
What is the purpose of Kirchhoff’s Voltage Law (KVL)?
A Distribution of voltage
B Conservation of current
C Voltage in a series circuit
D Total power in the circuit
Kirchhoff’s Voltage Law (KVL) states that the sum of all voltages in a closed loop must equal zero. This law is based on energy conservation, ensuring that energy supplied equals energy used.
What happens to the current in a parallel circuit?
A Remains the same
B Increases
C Decreases
D Divides into branches
In a parallel circuit, the total current is the sum of currents flowing through each branch. The current divides based on the resistance in each branch, with lower resistance branches carrying more current.
What is the impedance in AC circuits?
A Voltage across components
B Current
C Total opposition to current
D Resistance only
Impedance in AC circuits is the total opposition to current flow, combining both resistance and reactance (inductive and capacitive). It limits the flow of alternating current and is measured in ohms.
What is the role of a transformer?
A Change voltage level
B Increase current
C Filter noise
D Store energy
A transformer changes the voltage level in an AC circuit, either stepping it up or stepping it down. It works based on electromagnetic induction without changing the frequency of the current.
What does an electrical filter do?
A Increases frequency
B Reduces noise
C Boosts signal
D Changes voltage
An electrical filter removes unwanted frequencies from a signal, improving the clarity of communication or power transmission. It is used to eliminate noise and pass only the desired frequencies.
What is the power factor in an AC circuit?
A Voltage to current ratio
B Total energy consumption
C Ratio of real to apparent power
D Power loss
The power factor is the ratio of real power (the power that does useful work) to apparent power (the total power supplied). A power factor of 1 means no reactive losses and 100% efficiency.
What is a resistive circuit characterized by?
A Constant voltage
B Constant current
C Energy storage
D Opposition to current flow
A resistive circuit is characterized by resistors that oppose the flow of current. The power dissipated in the circuit is converted into heat, as described by Joule’s law.
What does the term “steady-state analysis” mean?
A Analyzing circuit when it is at equilibrium
B Analyzing circuit during transitions
C Analyzing only voltage
D Analyzing only current
Steady-state analysis refers to analyzing a circuit after all transient effects have settled and the system has reached equilibrium, meaning current and voltage remain constant over time.
What is a sine wave in AC circuits?
A Square wave
B Smooth oscillation
C Uniform waveform
D Random signal
A sine wave is the smooth, periodic oscillation typically seen in AC circuits. It represents alternating voltage or current with a specific frequency and amplitude, making it the foundation of AC analysis.
What is the result of resonance in a circuit?
A Increased impedance
B Maximum voltage drop
C Maximum power transfer
D No current flow
Resonance occurs in a circuit when the inductive and capacitive reactances are equal in magnitude but opposite in phase, allowing for maximum power transfer at a specific frequency.