Electronics MCQ & Objective Questions
Electronics is a crucial subject for students preparing for school exams and competitive tests in India. Mastering this topic not only enhances your understanding of fundamental concepts but also boosts your confidence in tackling objective questions. Practicing MCQs and important questions in Electronics helps you identify your strengths and weaknesses, ensuring effective exam preparation.
What You Will Practise Here
Basic concepts of current, voltage, and resistance
Understanding of Ohm's Law and its applications
Key components such as resistors, capacitors, and transistors
Fundamentals of circuit diagrams and analysis
Principles of alternating current (AC) and direct current (DC)
Signal processing and its applications in real-world scenarios
Important formulas related to power, energy, and circuit calculations
Exam Relevance
Electronics is a significant topic in various examinations, including CBSE, State Boards, NEET, and JEE. Students can expect questions that assess their understanding of basic concepts, circuit analysis, and application of theories. Common question patterns include multiple-choice questions that test both theoretical knowledge and practical application, making it essential to practice thoroughly.
Common Mistakes Students Make
Confusing the concepts of AC and DC, leading to incorrect answers.
Overlooking the significance of units in calculations, resulting in errors.
Misinterpreting circuit diagrams, which can lead to faulty analysis.
Neglecting to apply Ohm's Law correctly in problem-solving.
FAQs
Question: What are the key topics to focus on in Electronics for exams?Answer: Focus on circuit analysis, basic components, Ohm's Law, and signal processing.
Question: How can I improve my performance in Electronics MCQs?Answer: Regular practice of MCQs and understanding the underlying concepts will significantly enhance your performance.
Don't wait any longer! Dive into our Electronics MCQs and practice questions to solidify your understanding and excel in your exams. Your success starts with the right preparation!
Q. What happens to the voltage across a diode in a series circuit when it is reverse-biased?
A.
It becomes zero
B.
It increases
C.
It decreases
D.
It becomes negative
Show solution
Solution
When a diode is reverse-biased, the voltage across it increases until it reaches the breakdown voltage, at which point it can conduct in reverse.
Correct Answer:
B
— It increases
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Q. What happens to the voltage in an AC circuit over time?
A.
It remains constant
B.
It increases linearly
C.
It varies sinusoidally
D.
It decreases exponentially
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Solution
In an AC circuit, the voltage varies sinusoidally over time.
Correct Answer:
C
— It varies sinusoidally
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Q. What happens when a BJT is in saturation?
A.
It acts as an open switch
B.
It acts as a closed switch
C.
It is in the active region
D.
It is in cutoff
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Solution
When a BJT is in saturation, it acts as a closed switch, allowing maximum current to flow from collector to emitter.
Correct Answer:
B
— It acts as a closed switch
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Q. What is resonance in RLC circuits?
A.
The point where impedance is minimized
B.
The point where current is maximized
C.
The point where voltage is minimized
D.
The point where energy is stored
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Solution
Resonance in RLC circuits occurs when the current is maximized at a specific frequency.
Correct Answer:
B
— The point where current is maximized
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Q. What is the bandgap energy in semiconductor physics?
A.
The energy required to free an electron from the valence band
B.
The energy of the conduction band
C.
The energy of the valence band
D.
The energy lost during conduction
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Solution
The bandgap energy is the energy required to free an electron from the valence band to the conduction band in a semiconductor.
Correct Answer:
A
— The energy required to free an electron from the valence band
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Q. What is the bandgap energy in semiconductors?
A.
The energy required to free an electron
B.
The energy of the conduction band
C.
The energy of the valence band
D.
The energy lost during conduction
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Solution
The bandgap energy is the energy required to free an electron from the valence band to the conduction band in semiconductors.
Correct Answer:
A
— The energy required to free an electron
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Q. What is the bandgap energy of a typical silicon semiconductor?
A.
0.1 eV
B.
1.1 eV
C.
2.0 eV
D.
3.5 eV
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Solution
Silicon has a bandgap energy of approximately 1.1 eV, which is crucial for its semiconductor properties.
Correct Answer:
B
— 1.1 eV
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Q. What is the basic principle of operation of a transformer?
A.
Electromagnetic induction
B.
Capacitance
C.
Resistance
D.
Thermal conduction
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Solution
Transformers operate on the principle of electromagnetic induction.
Correct Answer:
A
— Electromagnetic induction
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Q. What is the behavior of an inductor at high frequencies?
A.
It acts as a short circuit
B.
It acts as an open circuit
C.
It has no effect
D.
It increases resistance
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Solution
At high frequencies, an inductor acts as an open circuit due to its reactance.
Correct Answer:
B
— It acts as an open circuit
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Q. What is the characteristic equation of a first-order system?
A.
s + 1/τ = 0
B.
s^2 + 1/τ = 0
C.
s + τ = 0
D.
s^2 + τ = 0
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Solution
The characteristic equation of a first-order system is s + 1/τ = 0, where τ is the time constant.
Correct Answer:
A
— s + 1/τ = 0
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Q. What is the characteristic equation of a second-order system?
A.
s^2 + 2ζω_ns + ω_n^2 = 0
B.
s^2 + ω_n^2 = 0
C.
s^2 + 2ω_ns + ζ = 0
D.
s^2 + 2s + 1 = 0
Show solution
Solution
The characteristic equation of a second-order system is s^2 + 2ζω_ns + ω_n^2 = 0, where ζ is the damping ratio and ω_n is the natural frequency.
Correct Answer:
A
— s^2 + 2ζω_ns + ω_n^2 = 0
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Q. What is the characteristic of the small-signal model of a diode?
A.
Linear resistance
B.
Constant voltage drop
C.
Variable capacitance
D.
Current source
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Solution
In the small-signal model of a diode, it is represented as a linear resistance (dynamic resistance) around the operating point.
Correct Answer:
A
— Linear resistance
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Q. What is the depletion region in a semiconductor diode?
A.
Region of high conductivity
B.
Region of low conductivity
C.
Region of high temperature
D.
Region of high voltage
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Solution
The depletion region in a semiconductor diode is a region of low conductivity where no free charge carriers are present due to recombination.
Correct Answer:
B
— Region of low conductivity
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Q. What is the effect of adding a capacitor in parallel with a resistor?
A.
It increases the total resistance
B.
It decreases the total resistance
C.
It creates a short circuit
D.
It affects the time constant
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Solution
Adding a capacitor in parallel with a resistor affects the time constant of the circuit, as it introduces a reactive component.
Correct Answer:
D
— It affects the time constant
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Q. What is the effect of adding a FET in series with a load?
A.
It decreases the load resistance
B.
It increases the load current
C.
It controls the load current
D.
It short-circuits the load
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Solution
A FET can control the load current based on the gate voltage applied, allowing for variable control in series circuits.
Correct Answer:
C
— It controls the load current
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Q. What is the effect of capacitance on the time response of an RC circuit?
A.
Increases time constant
B.
Decreases time constant
C.
No effect
D.
Increases current
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Solution
Increasing capacitance in an RC circuit increases the time constant (τ = R*C), leading to a slower time response.
Correct Answer:
A
— Increases time constant
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Q. What is the effect of connecting a diode in parallel with a resistor?
A.
It increases the resistance
B.
It allows current to bypass the resistor
C.
It blocks all current
D.
It changes the voltage across the resistor
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Solution
Connecting a diode in parallel with a resistor allows current to bypass the resistor when the diode is forward-biased.
Correct Answer:
B
— It allows current to bypass the resistor
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Q. What is the effect of increasing capacitance in an RC circuit?
A.
Faster response
B.
Slower response
C.
No effect
D.
Increased voltage
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Solution
Increasing capacitance in an RC circuit results in a slower response due to a larger time constant.
Correct Answer:
B
— Slower response
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Q. What is the effect of increasing resistance in a circuit while keeping voltage constant according to Ohm's Law?
A.
Current increases
B.
Current decreases
C.
Voltage increases
D.
Power increases
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Solution
According to Ohm's Law, if resistance increases while voltage remains constant, the current will decrease.
Correct Answer:
B
— Current decreases
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Q. What is the effect of increasing the feedback resistor (Rf) in a non-inverting op-amp configuration?
A.
Increases the output voltage
B.
Decreases the output voltage
C.
Increases the gain
D.
Decreases the gain
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Solution
Increasing the feedback resistor (Rf) in a non-inverting op-amp configuration increases the gain.
Correct Answer:
C
— Increases the gain
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Q. What is the effect of increasing the frequency of an AC signal on a capacitor in a circuit?
A.
It blocks the signal
B.
It allows more current to pass
C.
It has no effect
D.
It increases the impedance
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Solution
As the frequency of an AC signal increases, a capacitor allows more current to pass due to its decreasing reactance.
Correct Answer:
B
— It allows more current to pass
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Q. What is the effect of increasing the frequency of an AC signal on a diode?
A.
Increases forward voltage drop
B.
Decreases reverse recovery time
C.
Increases reverse breakdown voltage
D.
Decreases forward current
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Solution
Increasing the frequency of an AC signal decreases the reverse recovery time of a diode, allowing it to switch faster.
Correct Answer:
B
— Decreases reverse recovery time
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Q. What is the effect of increasing the frequency on the reactance of a capacitor?
A.
Reactance increases
B.
Reactance decreases
C.
Reactance remains the same
D.
Reactance becomes infinite
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Solution
The reactance of a capacitor decreases with increasing frequency, allowing more AC current to pass.
Correct Answer:
B
— Reactance decreases
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Q. What is the effect of increasing the gate voltage in an n-channel FET?
A.
Decreases current
B.
Increases current
C.
No effect
D.
Reverses current direction
Show solution
Solution
Increasing the gate voltage in an n-channel FET enhances the channel conductivity, thus increasing the current.
Correct Answer:
B
— Increases current
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Q. What is the effect of increasing the load resistance on the power delivered to the load in a resistive circuit?
A.
Power increases
B.
Power decreases
C.
Power remains constant
D.
Power becomes zero
Show solution
Solution
Increasing the load resistance generally decreases the power delivered to the load, according to Ohm's law.
Correct Answer:
B
— Power decreases
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Q. What is the effect of increasing the number of turns in an inductor?
A.
Inductance decreases
B.
Inductance remains the same
C.
Inductance increases
D.
Inductance becomes zero
Show solution
Solution
Increasing the number of turns in an inductor increases its inductance.
Correct Answer:
C
— Inductance increases
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Q. What is the effect of increasing the number of turns in the primary winding of a transformer?
A.
Increases the output current
B.
Decreases the output voltage
C.
Increases the output voltage
D.
Has no effect on the output
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Solution
Increasing the number of turns in the primary winding increases the output voltage in a step-up transformer.
Correct Answer:
C
— Increases the output voltage
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Q. What is the effect of increasing the resistance in an RL circuit?
A.
Increases the current
B.
Decreases the current
C.
Has no effect on current
D.
Increases the voltage
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Solution
Increasing the resistance in an RL circuit decreases the current according to Ohm's law.
Correct Answer:
B
— Decreases the current
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Q. What is the effect of increasing the value of feedback resistor Rf in a non-inverting op-amp?
A.
Increases output voltage
B.
Decreases output voltage
C.
Increases input impedance
D.
Decreases input impedance
Show solution
Solution
Increasing Rf in a non-inverting op-amp configuration increases the output voltage.
Correct Answer:
A
— Increases output voltage
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Q. What is the effect of increasing the voltage across a capacitor?
A.
It decreases the capacitance
B.
It increases the stored charge
C.
It causes the capacitor to short circuit
D.
It has no effect
Show solution
Solution
Increasing the voltage across a capacitor increases the amount of charge stored, as capacitance is constant.
Correct Answer:
B
— It increases the stored charge
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