A resistor limits the current flow in a circuit by providing resistance. It ensures that the current doesn’t exceed safe levels, protecting components and controlling the flow of electricity based on Ohm’s law.
What is the function of a capacitor in a circuit?
A Limit power
B Change voltage
C Store current
D Store energy
A capacitor stores energy in an electric field between its plates. When charged, it holds this energy and releases it when needed, helping to smooth out voltage fluctuations in circuits or filter signals.
How does an inductor oppose current?
A By creating voltage
B By storing charge
C By storing energy
D By creating resistance
An inductor opposes changes in current by generating a voltage across its terminals, which resists the change in current. This is a result of the magnetic field it creates when current flows through it.
What happens to the total capacitance when capacitors are connected in series?
A Stays same
B Divides
C Decreases
D Increases
When capacitors are connected in series, the total capacitance decreases. The reciprocal of the total capacitance is the sum of the reciprocals of the individual capacitances, which results in a lower overall capacitance.
What is the unit of resistance?
A Ohm
B Watt
C Volt
D Ampere
The unit of resistance is the ohm (Ω), named after Georg Simon Ohm. Resistance is a measure of how much a material opposes the flow of electric current in a circuit.
What does an inductor store?
A Voltage
B Energy
C Power
D Current
An inductor stores energy in the form of a magnetic field. When current flows through the coil, the magnetic field builds up, storing energy which is released when the current changes.
In a resistive circuit, how is the current related to the voltage?
A Unrelated
B Zero
C Directly proportional
D Inversely proportional
In a resistive circuit, the current is directly proportional to the voltage according to Ohm’s law (V = I * R). As voltage increases, current increases, assuming resistance remains constant.
What happens to the total inductance when inductors are connected in series?
A Increases
B Stays same
C Decreases
D Divides
When inductors are connected in series, the total inductance increases. The total inductance is the sum of the individual inductances, meaning the system’s ability to resist changes in current increases.
What type of current flows in a capacitive circuit?
A Both
B DC
C AC
D Zero
Capacitors only allow alternating current (AC) to pass after charging. In a DC circuit, capacitors eventually block the current after being fully charged, but in AC circuits, they continuously charge and discharge.
What is the main effect of increasing resistance in a circuit?
A Increases power
B Decreases voltage
C Increases current
D Decreases power
Increasing the resistance in a circuit decreases the power. According to the formula P=V²/R, as resistance increases for a constant voltage, power decreases due to the higher opposition to current flow.
What is the primary use of an inductive circuit?
A Frequency filtering
B Energy storage
C Voltage regulation
D Current control
Inductive circuits are primarily used to store energy in a magnetic field when current flows through an inductor. This stored energy can later be released to maintain current flow or control fluctuations in current.
What happens when a resistor and capacitor are connected in series in an AC circuit?
A Resistor blocks current
B Capacitor blocks DC
C Total impedance increases
D Inductive behavior
In an AC circuit with a resistor and capacitor in series, the total impedance increases because the impedance of the capacitor adds to the resistance. This results in a higher overall opposition to current flow.
How does current behave in a purely resistive AC circuit?
A In phase with voltage
B Leads voltage
C Lags voltage
D Opposes voltage
In a purely resistive AC circuit, the current is in phase with the voltage, meaning the peak values of both current and voltage occur at the same time. There is no phase shift between them.
What is the role of a resistor in an AC circuit?
A Create voltage
B Control frequency
C Limit current
D Store energy
A resistor in an AC circuit limits the current flow, based on its resistance. It dissipates energy as heat and ensures that the current does not exceed a safe level in the circuit.
What does a capacitor do in a DC circuit after being fully charged?
A Converts current
B Blocks current
C Allows current
D Stores power
In a DC circuit, a capacitor blocks the current after it is fully charged. After charging, the capacitor behaves like an open circuit, preventing any further DC current flow, although it can store and release energy.