Electronics MCQs
In a semiconductor, the forbidden energy gap is of the order of:
The process of adding impurities to a pure semiconductor is called:
Doping
Annealing
Diffusion
Depletion
In a p-type semiconductor, the majority charge carriers are:
Electrons
Protons
Holes
Neutrons
The depletion region of a p-n junction is so named because it is depleted of:
Atoms
Mobile charge carriers
Impurities
Potential barrier
When a p-n junction is forward biased, the width of the depletion region:
Increases
Decreases
Remains the same
Becomes zero
A diode is a device that allows current to flow in:
Both directions
One direction only
Neither direction
A circular path
The process of converting AC to DC is called:
Amplification
Rectification
Oscillation
Modulation
In a half-wave rectifier, the output frequency is _______ the input frequency.
A Zener diode is designed to operate in the:
Forward bias region
Reverse breakdown region
Saturation region
Cut-off region
A photodiode is operated in:
Forward bias
Reverse bias
No bias
Breakdown region
The V-I characteristic curve for a silicon diode is shown. The point 'V_k' on the graph represents the:
Breakdown Voltage
Peak Inverse Voltage
Knee Voltage
Zener Voltage
When a transistor is used as a digital switch, it operates in which two regions?
Active and Saturation
Cut-off and Active
Saturation and Cut-off
Active and Breakdown
In a common-emitter transistor, the emitter current (Ie) is 8.0 mA and the collector current (Ic) is 7.9 mA. What is the current gain (beta)?
A transistor has how many doped regions?
In a PNP transistor, the charge carriers are mainly:
Electrons
Holes
Both electrons and holes
Ions
The base of a transistor is:
Heavily doped
Lightly doped and thin
Moderately doped and thick
Heavily doped and thick
For a transistor to act as an amplifier, the emitter-base junction must be:
Forward biased and the collector-base junction reverse biased
Reverse biased and the collector-base junction forward biased
Both junctions forward biased
Both junctions reverse biased
The current gain of a common-emitter amplifier is given by the symbol:
The relationship between alpha and beta is:
beta = alpha / (1 - alpha)
alpha = beta / (1 - beta)
beta = alpha / (1 + alpha)
alpha = beta / (1 + beta)
What is the primary function of a capacitor placed in parallel with the load resistor in a rectifier circuit?
To block the DC component
To store charge during peaks and supply it to the load during troughs
To increase the frequency of the output voltage
To protect the diode from excessive reverse voltage
The conductivity of an intrinsic semiconductor increases with an increase in temperature primarily because:
The forbidden energy gap increases
The number of charge carriers (electron-hole pairs) increases
The mobility of charge carriers increases
The semiconductor becomes a p-type material
An ideal operational amplifier (Op-Amp) should have:
High input impedance and high output impedance
Low input impedance and low output impedance
High input impedance and very low output impedance
Low input impedance and high output impedance
An operational amplifier (op-amp) has a very high:
Input impedance
Output impedance
Current gain
Power consumption
In an inverting amplifier, the output signal is:
180 degrees out of phase with the input signal
In phase with the input signal
90 degrees out of phase with the input signal
Independent of the input signal
An oscillator is a circuit that produces:
A DC output from an AC input
An amplified output from a small input
A periodic waveform without any input signal
A constant voltage output
Which of the following is a digital quantity?
Temperature of a room
Speed of a car
Number of students in a class
Height of a person
The binary number system has a base of:
Which logic gate is known as the universal gate?
The output of an AND gate is HIGH only when:
All inputs are HIGH
All inputs are LOW
Any input is HIGH
Any input is LOW
The Boolean expression for an OR gate is:
Y = A . B
Y = A + B
Y = A'
Y = (A + B)'
A NOT gate is also known as an:
Inverter
Buffer
Follower
Converter
The ripple factor of a full-wave rectifier is:
In a common-base amplifier, the current gain alpha is always:
Greater than 1
Less than 1
Equal to 1
Infinite
The voltage gain of a non-inverting op-amp is given by:
Av = -Rf/Ri
Av = 1 + Rf/Ri
Av = Rf/Ri
Av = 1 - Rf/Ri
A bistable multivibrator is also known as a:
Flip-flop
Clock
Counter
Register
The efficiency of a full-wave rectifier is approximately:
The output of a NOR gate is HIGH only when:
All inputs are HIGH
All inputs are LOW
Any input is HIGH
Any input is LOW
The decimal equivalent of the binary number 1011 is:
In a common-emitter amplifier, the output voltage is taken from the:
Emitter
Collector
Base
Ground
An LED (Light Emitting Diode) emits light when:
Forward biased
Reverse biased
No bias is applied
It is heated
A transistor can be used as a:
Switch
Amplifier
Both a switch and an amplifier
Neither a switch nor an amplifier
The output of an XOR gate is HIGH when:
The inputs are the same
The inputs are different
Both inputs are HIGH
Both inputs are LOW
The potential barrier for silicon at room temperature is approximately:
A filter circuit is used to:
Convert AC to DC
Smooth the pulsating DC output of a rectifier
Amplify the DC output
Regulate the DC output
The gain of an amplifier without feedback is known as:
Closed-loop gain
Open-loop gain
Voltage gain
Current gain
In a bridge rectifier, how many diodes are used?
Zener breakdown in a p-n junction occurs due to:
The thermal breakdown of covalent bonds
The collision of minority carriers with atoms
The rupture of covalent bonds by a strong electric field
The diffusion of majority carriers across the junction
A logic circuit consists of a two-input AND gate followed by a NOT gate. This combination is equivalent to a single:
NOR gate
XOR gate
OR gate
NAND gate
What is the result of the binary addition 1101 + 0110?
In the circuit shown, if the input is a sine wave, which component is primarily responsible for converting the pulsating DC into a smoother DC?
Transformer
Diode D1
Load Resistor R_L
Capacitor C
The Boolean expression A + A'B is equivalent to:
The collector of a transistor is:
Heavily doped
Lightly doped
Moderately doped and largest in size
Not doped
An op-amp can be used as a comparator to:
Compare two voltages
Amplify a single voltage
Generate a sine wave
Store a voltage
De Morgan's first theorem states that (AB)' is equal to:
The resistance of a reverse-biased p-n junction is:
Very low
Very high
Zero
Infinite
In a conductor, the valence band and conduction band:
Are separated by a large gap
Are separated by a small gap
Overlap each other
Are both empty
The number of diodes required in a center-tapped full-wave rectifier is:
Which of the following is an active component?
Resistor
Capacitor
Inductor
Transistor
The phase difference between the input and output of a common-emitter amplifier is:
0 degrees
90 degrees
180 degrees
270 degrees
A device that converts electrical energy into light energy is:
Photodiode
LED
Zener diode
Rectifier diode
Other Physics Topics MCQs
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