Free Electronics and Devices MCQs with Answers

• A. highest conductivity
• B. lowest temperature co-efficient
• C. good mechanical strength
• D. good corrosion resistance
• E. easy solderable and drawable quality
• F. all of the above

Explanation: A practical highly conductive material should combine high conductivity with a low temperature coefficient, mechanical strength, corrosion…

• A. 2
• B. 4
• C. 6
• D. 8

Explanation: In a simple cubic lattice, each atom has four neighbours in its own plane plus one along each of the three-dimensional opposite…

• A. less than that of unbounded electron
• B. greater than that of unbounded electron
• C. equal to that of unbounded electron
• D. infinite
• E. none of the above

Explanation: A bound electron is confined to an atom and has less available energy than a free or unbound electron in the elementary energy-band…

• A. copper
• B. aluminium
• C. both (A) and (B)
• D. copper and silver
• E. platinum and gold

Explanation: Copper and aluminium are the most commonly used conducting materials because they combine good conductivity with practical cost and…

• A. zero conductivity
• B. unity conductivity
• C. infinite conductivity
• D. none of the above

Explanation: A perfect conductor has zero resistance, and since conductivity is the reciprocal of resistivity, its conductivity is treated as infinite.

• A. 2n2
• B. 4n2
• C. 2n3
• D. 4ns

Explanation: The maximum number of electrons in the nth principal energy level is given by 2n².

• A. malleability
• B. toughness
• C. softness
• D. none of the above

Explanation: Hardness is resistance to scratching, indentation or deformation, so its converse is softness.

• A. Proton
• B. Neutron
• C. Electron
• D. None of the above

Explanation: An electron carries a negative electric charge and moves around the positively charged nucleus.

• A. unit cell
• B. space lattice
• C. either A. or (b)
• D. none of the above

Explanation: A unit cell is the smallest repeating block of atoms whose repetition builds the crystal structure.

• A. transfer of electrons between atoms
• B. sharing of electrons between atoms
• C. sharing of variable number of electrons by a variable number of atoms
• D. none of the above

Explanation: A covalent bond forms when atoms share one or more pairs of valence electrons. Transfer of electrons is characteristic of an ionic bond.

• A. Less than 5
• B. Less than 10
• C. More than 10
• D. None of the above

Explanation: A tuned amplifier is designed to respond strongly around one narrow resonant frequency, so its quality factor is normally high, commonly…

• A. IF
• B. Audio
• C. Output
• D. None of the above

Explanation: Double-tuned circuits provide good selectivity together with the required bandwidth in the intermediate-frequency section of a radio…

• A. Loose
• B. Tight
• C. Critical
• D. None of the above

Explanation: Loose coupling gives a narrower resonance curve and therefore better selectivity.

• A. Sensitivity
• B. Fidelity
• C. Selectivity
• D. None of the above

Explanation: The Q-factor of a tuned circuit indicates how sharply it responds around resonance.

• A. 10kHz
• B. 40 kHz
• C. 30 kHz
• D. 20 kHz

Explanation: For a tuned circuit, Q = fr/BW, so BW = fr/Q = 1000 kHz/50 = 20 kHz. The resonant frequency and Q directly determine the bandwidth.

• A. A pure resistive
• B. A pure inductive
• C. A pure capacitive
• D. A resonant tank

Explanation: A class C transistor conducts for less than half a cycle, so its pulsed output must be shaped by a tuned resonant circuit.

• A. Resistive
• B. Capacitive
• C. LC tank
• D. Inductive

Explanation: A tuned amplifier uses a resonant LC tank as its load, giving high impedance and maximum voltage gain near the selected resonant…

• A. Radio frequency
• B. Low frequency
• C. Audio frequency
• D. None of the above

Explanation: Tuned amplifiers are designed to select and amplify a narrow band of frequencies, which is especially useful in radio-frequency receivers…

• A. Minimum
• B. Maximum
• C. Half-way between maximum and minimum
• D. Zero

Explanation: At resonance, the tuned load provides the intended maximum impedance and signal response at its selected frequency.

• A. Class A
• B. Class C
• C. Class B
• D. None of the above

Explanation: Tuned amplifiers commonly use Class C operation because its high efficiency suits narrowband RF amplification.