Free Electronics MCQs with Answers

• A. 1.5 Ω
• B. 5 Ω
• C. 6.67 Ω
• D. 200 Ω

Explanation: Given:Voltage source = V = 1.5VVoltage drop across diode = Vd = 0.05Maximum power rating = Pmax = 100 mW = 0.1 WAccording to P = Vd x I…

• A. No current flows because diode is reverse-biased
• B. Current flows because diode is forward-biased
• C. Breakdown occurs
• D. Depletion region increases significantly

Explanation: The P-side is connected to the positive terminal and the N-side to the negative terminal → forward bias.

• A. Zero
• B. 0.02
• C. 0.03
• D. 0.036

Explanation: The total resistance in the circuit is the sum of the diode resistances and the 100 Ω resistance, giving a total of 300 Ω.Using Ohm's law…

• A. Zero
• B. Same as the input
• C. Full wave rectified
• D. Half wave rectified

Explanation: In the figure, the input is across terminals A and C, and the output is across terminals B and D. Then, the output is full-wave rectified.

• A. 5A
• B. 2A
• C. 1A
• D. Zero

Explanation: In the circuit the diode is reverse-biased. So, no current flows through the circuit.

• A. C
• B. A
• C. B, D
• D. A, B, C, D

Explanation: Considering the typical behaviour of a full-wave rectifier, option 3 (BD) is the most likely correct answer.

• A. A
• B. B
• C. C
• D. D

Explanation: The diode shown acts as a half wave rectifier hence it only rectifies half of the cycle.

• A. Constant current
• B. Constant voltage
• C. Constant resistance
• D. None of them

Explanation: Because once the reverse voltage reaches the Zener breakdown voltage, the voltage across the diode stays nearly constant even if the…

• A. Current flows freely
• B. Depletion layer reduces
• C. Very small leakage current flows
• D. Diode conducts heavily

Explanation: Here, the P-side is connected to negative and the N-side to positive, so the diode is reverse-biased.

• A. 1.12 ev
• B. 0.02 ev
• C. 6.72 ev
• D. 7.2 ev

Explanation: The correct answer is c) 6.72 eV because it accurately represents the bandgap energy of germanium.

• A. Decrease
• B. Remains constant
• C. Increase
• D. None of these

Explanation: The purpose of doping is to increase the number of free electrons or holes in the semiconductor crystal.

• A. Electrons only
• B. Holes only
• C. Both electrons and holes
• D. Neither holes nor electrons

Explanation: The depletion region of a p-n junction contains neither free electrons nor holes.

• A. Electrically neutral
• B. Negatively charged
• C. Positively charged
• D. None of these

Explanation: p-type and n-type semiconductors are formed when impurity atoms, which are themselves electrically neutral, are added to a pure…

• A. Conductors
• B. Semi conductors
• C. Insulators
• D. All of the above

Explanation: Holes are formed when electrons in atoms move out of the valence band (the outermost shell of the atom that is completely filled with…

• A. A detector
• B. A rectifier
• C. An amplifier
• D. None of these

Explanation: p-n junction is also known as a diode.It is a device that is composed of p-type and n-type semiconductors.Its half part is made up of…

• A. A positive charge
• B. A negative charge
• C. A neutral
• D. None of these

Explanation: In an applied electric field, the electrons move in one direction, corresponding to the hole moving in the other.

• A. Large forbidden energy gap
• B. No valance electron
• C. Overlapping valance & conduction band
• D. None of these

Explanation: When a covalent bond breaks, then the electrons get freed from an atom.

• A. Insulator
• B. Semi-conductor
• C. Dielectric
• D. Conductor

Explanation: Silicon, a very common element, is used as the raw material of semiconductors because of its stable structure.Silicon is also less…

• A. Insulater
• B. Conductor
• C. Semi-conductor
• D. None of these

Explanation: In silicon, the crystalline form is a silvery, metallic-looking substance.

• A. Insulator
• B. Conductor
• C. Semi-conductor
• D. None of these

Explanation: At room temperature, pure silicon and germanium would have enough free charge carriers to be classified as a semiconductor.