Ohm’s law states that the voltage across a resistor is directly proportional to the current flowing through it, with resistance being the constant of proportionality. It is fundamental in analyzing resistive circuits.
What does Kirchhoff’s Current Law (KCL) state?
A Total voltage across a loop equals zero
B Total current entering a junction equals current leaving
C Current is inversely proportional to resistance
D Total power in a circuit is conserved
Kirchhoff’s Current Law (KCL) states that the total current entering a junction in a circuit is equal to the total current leaving. It is based on the conservation of electric charge in a circuit.
How does the total resistance in a series circuit behave?
A Decreases with each added resistor
B Remains constant
C Increases with each added resistor
D Depends on current
In a series circuit, the total resistance increases as more resistors are added. The total resistance is the sum of the individual resistances, resulting in a greater opposition to the flow of current.
What is the voltage across all resistors in a parallel circuit?
A Varies with resistance
B Decreases with resistance
C Divides equally
D Equal to the source voltage
In a parallel circuit, the voltage across each resistor is the same as the source voltage. Each branch experiences the same potential difference, regardless of the resistance value in the branches.
What does an inductor do in a circuit?
A Stores energy in a magnetic field
B Stores energy in an electric field
C Resists changes in voltage
D Allows high frequencies to pass
An inductor stores energy in the form of a magnetic field when current flows through it. It resists changes in current and is often used in filters and inductive circuits to control current flow.
What happens when capacitors are connected in series?
A Total capacitance increases
B Total capacitance decreases
C No change in capacitance
D Total capacitance remains the same
In a series connection, the total capacitance is less than the smallest individual capacitance. The reciprocal of the total capacitance is the sum of the reciprocals of the individual capacitances in the series.
In a purely resistive circuit, what is the phase relationship between current and voltage?
A Voltage leads current
B Current leads voltage
C In phase
D Out of phase
In a purely resistive circuit, the current and voltage are in phase, meaning their peaks occur at the same time. This is because resistors do not create any phase shift between current and voltage.
What is the role of a capacitor in a transient analysis of a circuit?
A Amplify signals
B Store current
C Store energy and resist changes in current
D Store energy and resist changes in voltage
In transient analysis, capacitors store energy in an electric field and oppose changes in voltage. They charge and discharge during transitions in the circuit, impacting how voltage changes over time.
What does an AC voltage source provide in an electrical circuit?
A Varying voltage in a sinusoidal waveform
B Constant voltage
C Pulsating current
D DC voltage
An AC voltage source provides a voltage that varies sinusoidally with time, alternating in polarity. This allows the current to alternate, which is typical in most electrical power distribution systems.
What does a feedback mechanism in an amplifier circuit do?
A Increases efficiency
B Improves stability and gain control
C Controls current
D Filters unwanted signals
A feedback mechanism in an amplifier circuit helps improve stability by feeding a portion of the output back to the input. It controls the gain and reduces distortion, enhancing the amplifier’s performance.
What is an equivalent circuit used for?
A Increase resistance
B Increase current
C Simplify complex circuits
D Store electrical energy
An equivalent circuit simplifies a complex circuit by representing it with a combination of basic elements like resistors, capacitors, and inductors. This makes the circuit easier to analyze and solve, especially in complex systems.
What does an energy transfer mechanism in an electric circuit typically involve?
A Storing energy
B Increasing the voltage
C Filtering noise
D Converting electrical energy into another form of energy
Energy transfer in an electric circuit typically involves converting electrical energy into mechanical, thermal, or light energy, such as in motors, heaters, and light bulbs. This is the main purpose of most electrical devices.
How do series circuits behave when more components are added?
A Total current decreases
B Total current increases
C Total resistance decreases
D Voltage divides evenly
In a series circuit, adding more components increases the total resistance. According to Ohm’s law, this results in a decrease in the total current for a given voltage, as resistance and current are inversely proportional.
How does the impedance of a series R-L circuit change with increasing frequency?
A Decreases
B Increases
C Remains constant
D Increases then decreases
The impedance of a series R-L circuit increases with frequency because the inductive reactance increases with frequency. This results in more opposition to current flow as the frequency of the AC signal increases.
What is the effect of feedback in an operational amplifier (op-amp) circuit?
A Increases gain
B Reduces gain
C Stabilizes output
D Increases voltage
Feedback in an operational amplifier circuit stabilizes the output by controlling the gain and reducing distortions. By feeding part of the output back to the input, it ensures that the amplifier operates in a predictable and controlled manner.