NEET Physics: Diode as a rectifier Practice Questions
13 free multiple-choice questions on Diode as a rectifier (Semiconductors) for NEET Physics, each with the correct answer and a step-by-step explanation. Attempt a question, then reveal the solution to check your reasoning.
Practice thousands more NEET questions in the app →Q1. What is the main characteristic of a reverse-biased diode regarding current flow?
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Correct answer: A — It blocks current flow (acts as an open circuit)
When a diode is reverse biased, it acts almost like an open circuit, strongly resisting the flow of current.
Q2. In a half-wave rectifier circuit, the output waveform consists of:
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Correct answer: C — A continuous pulsating DC signal
A half-wave rectifier allows only one half cycle of the input AC to pass through, resulting in a pulsating DC output with only half the input frequency.
Q3. In a practical rectifier circuit, what component is usually placed across the load resistor in a half-wave rectifier to ensure proper operation?
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Correct answer: A — A series resistor (load)
A load resistor is necessary to draw the current flowing through the diode and the load, establishing the actual power transfer and determining the output voltage characteristics of the circuit.
Q4. In a forward-biased diode, the voltage across the diode is generally
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Correct answer: D — Positive
When a diode is forward-biased, it allows current to flow, and the voltage drop across it is positive (approximately 0.7V for Silicon diodes), meaning the voltage across the diode is positive relative to the anode.
Q5. In a rectifier circuit, the primary role of the diode is to act as a control element that allows current to flow easily in which direction and blocks flow in the other direction?
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Correct answer: D — Forward bias, reverse blocking
A diode is a semiconductor device that allows current to flow easily when it is forward biased (positive voltage on the anode) and blocks current flow when it is reverse biased (negative voltage on the anode).
Q6. The main reason a diode is used as a rectifier element is due to its property of having a
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Correct answer: B — Non-linear I-V characteristic
The non-linear current-voltage (I-V) characteristic, specifically the large forward voltage drop when conducting, allows it to control the flow of current directionally, which is the basis of rectification.
Q7. In the context of a semiconductor diode, what happens to the resistance when the diode is operating in the forward bias region?
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Correct answer: D — The resistance decreases significantly
When a diode is forward-biased (and conducting), it acts like a closed switch with a very small voltage drop (approximately 0.7V for Silicon), thus allowing the current to flow with minimal opposition, effectively making its resistance very low.
Q8. In which bias condition does a P-N junction diode act as an open circuit?
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Correct answer: D — Reverse bias
When a diode is reverse biased, the depletion region widens, and it acts like an open switch, blocking the flow of current effectively.
Q9. Which condition allows a p-n junction diode to act as a closed switch, allowing current to flow significantly from the anode to the cathode?
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Correct answer: D — Forward Bias
Forward bias occurs when a positive voltage is applied to the p-side and a negative voltage to the n-side of the diode. This reduces the potential barrier, allowing current to flow when the applied voltage exceeds the knee voltage (approx 0.7V for Silicon).
Q10. The process of converting Alternating Current (AC) into pulsating Direct Current (DC) is known as:
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Correct answer: B — Rectification
Rectification is the process performed by diodes to convert the time-varying AC input into a pulsating DC output.
Q11. If a diode is forward biased, what is the approximate voltage drop across the ideal diode?
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Correct answer: B — The forward voltage drop (V_f or Vₒₙ)
In an ideal diode, when forward biased, the voltage drop across the diode is the fixed forward voltage drop (V_f).
Q12. The process of rectification fundamentally involves converting which type of input signal to the output signal?
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Correct answer: B — AC to Pulsating DC
Rectification is the process of taking an alternating current (AC) input and converting it into a pulsating direct current (DC) output.
Q13. The ideal behavior of a diode when reverse-biased is that it acts as a
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Correct answer: C — Open circuit
In an ideal diode, when reverse-biased, it blocks the flow of current completely, behaving like an open circuit.
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