Free Electronics and Devices MCQs with Answers

• A. charged
• B. short-circuited
• C. lossy
• D. satisfactory

Explanation: A healthy capacitor initially shows low resistance while charging, then the ohmmeter reading rises; a reading that immediately falls to…

• A. stable operation
• B. accurate value
• C. low leakage reactance
• D. low losses

Explanation: Mica capacitors are valued for stable operation, accurate capacitance, and low dielectric losses.

• A. the uncharged conductor gets charged by conduction
• B. the uncharged conductor gets charged by induction and then attracted towards the charging body
• C. the uncharged conductor is attracted first and then charged by induction
• D. it remains as suchTry CAD Software

Explanation: A nearby charged conductor polarizes the uncharged conductor by induction, producing opposite charge nearer to it and hence a net…

• A. always polarised
• B. usually of fixed value
• C. electrolytic condenser
• D. a variable condenser

Explanation: Paper capacitors are generally non-polarized, fixed-value capacitors used where moderate capacitance and insulation are required.

• A. Aluminium foil capacitor
• B. Mica capacitor
• C. Ceramic capacitor
• D. Paper capacitorGet Study Guides

Explanation: For the same capacitance and voltage rating, a ceramic dielectric generally provides a higher dielectric constant and dielectric strength…

• A. low capacitance
• B. fixed capacitance
• C. variable capacitance
• D. large value of capacitance

Explanation: Electrolytic capacitors achieve high capacitance using a very thin oxide dielectric and a large effective electrode area.

• A. metallic plate variable gang condenser
• B. metallic paper capacitor
• C. oil impregrated paper condenser
• D. poled aluminium electrolytic condenser

Explanation: A poled aluminium electrolytic capacitor is designed for one-way voltage and must not be subjected to reverse DC voltage.

• A. Air capacitor
• B. Electrolytic capacitor
• C. Mica capacitor
• D. none of the above

Explanation: Mica capacitors have low dielectric losses, good stability and a high self-resonant frequency, making them suitable for high-frequency…

• A. J/mm
• B. C/m2
• C. kV/mm
• D. N/mm

Explanation: Dielectric strength is the maximum electric field a material can withstand before breakdown, so it is expressed as voltage per unit…

• A. Air
• B. Glass
• C. Bakelite
• D. Paper

Explanation: Bakelite is a strong, heat-resistant insulating material with good dielectric properties, making it the superior choice among these…

• A. Air
• B. Mica
• C. Plastic film
• D. Ceramic

Explanation: Mica capacitors have low loss and excellent stability, making them suitable for coupling and tuning circuits, including radio-frequency…

• A. Mica
• B. Paper
• C. Ceramic
• D. Electrolytic

Explanation: Electrolytic capacitors use a very thin oxide dielectric, but their construction and dielectric system generally provide the lowest…

• A. Ceramic capacitor
• B. Paper capacitor
• C. Both will be of equal size
• D. None of the above

Explanation: For the same capacitance and voltage rating, ceramic capacitors are usually smaller because ceramic dielectrics provide higher…

• A. Ceramic capacitor
• B. Mica capacitor
• C. Both will have identical value of capacitance
• D. It depends on applied voltage

Explanation: Capacitance is proportional to dielectric permittivity when plate area and separation are fixed, and ceramic generally has a higher…

• A. 1
• B. 10
• C. 100
• D. 1000

Explanation: Relative permittivity is the ratio of a material's permittivity to the permittivity of free space, so free space itself has a relative…

• A. polarised capacitor
• B. variable capacitor
• C. ceramic capacitor
• D. none of the above

Explanation: A gang condenser mechanically connects two or more variable capacitor sections so their capacitances change together.

• A. 10 to 400 pF
• B. 1 to 20 pF
• C. 100 to 900 pF
• D. 20 to 100 pF

Explanation: Variable air capacitors used in tuning circuits are commonly available over approximately 10 to 400 pF.

• A. 10 F
• B. 10 uF
• C. 100 nF
• D. 1000 uF

Explanation: Using C = Q/V, the capacitance is 2000 μC ÷ 200 V = 10 μF. The other choices result from incorrect unit conversion or arithmetic.

• A. increase in plate area and decrease in distance between the plates
• B. increase in plate area and distance between the plates
• C. decrease in plate area and value of applied voltage
• D. reduction in plate area and distance between the plates

Explanation: For a parallel-plate capacitor, C = εA/d, so increasing plate area A and reducing plate spacing d both increase capacitance.

• A. 0.0002
• B. 0.002
• C. 0.02
• D. 0.2

Explanation: The dissipation factor, or tan δ, of a good dielectric is very small, commonly around 10⁻⁴ to 10⁻³.