200+ Capacitance and Capacitor MCQ – Objective Question Answer for Capacitance and Capacitor Quiz

191. The current in conductors connecting the voltage source to the plates of a capacitor is _______

A. Conduction current
B. Leakage current
C. Charging current
D. Displacement current

Answer: C

The current in conductors connecting the voltage source to the plates of a capacitor is the charging current and not the conduction or leakage current.

 

192. Under normal conditions capacitors have _______

A. Displacement current
B. Conduction current
C. Both conduction and displacement current
D. Neither conduction nor displacement current

Answer: A

Under normal conditions, capacitors contain an insulating material called dielectric sandwiched between the plates of the capacitor. Since insulators can carry only an electric field but not moving carriers, therefore normally a capacitor has a displacement current and not a conduction current.

 

193. What is the unit for displacement current?

A. No unit
B. Ampere
C. Coulomb
D. Ampere/coulomb

Answer: B

Displacement current is a type of current and hence it has the same unit as that of current that is ampere.

 

194. Displacement current depends on ___________

A. Moving charges
B. Change in time
C. Both moving charges and change in time
D. Neither moving charges nor change in time

Answer: B

Displacement current is the current which arises due to variations in the field. Hence, it does not depend on the moving charges but it changes with time which causes variation in the field.

 

195. Magnetic fields between the parallel plates of a capacitor are due to?

A. Displacement current
B. Conduction current
C. Both conduction and displacement current
D. Neither conduction nor displacement current

Answer: A

Displacement current is the current which arises due to variations in the field. Change in the field results in the formation of magnetic fields. Hence displacement currents lead to the magnetic field between the plates of a capacitor.

 

196. The free electrons in practical dielectrics are due to ________

A. There are no free electrons
B. Conductors
C. Impurities
D. Displacement currents

Answer: C

Ideally, dielectrics are insulators and do not contain any free electrons. But no dielectric is a perfect dielectric, hence the free electrons are due to impurities present in each dielectric.

 

197. The flow of electrons which does not pass through the battery is known as ____________

A. Conduction current
B. Leakage current
C. Charging current
D. Displacement current

Answer: A

Conduction current is the flow of electrons from the positive plate of the capacitor to the negative plate of the capacitor, not through the battery. Hence the type of current which flows without passing through the battery is conduction current.

 

198. Paper capacitor is a type of _________

A. Fixed capacitor
B. Variable capacitor
C. Either fixed or variable depending on its usage
D. Neither fixed nor variable

Answer: A

Paper capacitors are fixed capacitors because, like fixed capacitors, their capacitance value remains constant. In paper capacitors, paper is used as the dielectric.

 

199. A capacitor using chemical reactions to store charge is _______

A. Paper capacitor
B. Ceramic capacitor
C. Polyester capacitor
D. Electrolyte capacitor

Answer: D

Electrolyte capacitors use chemical processes like pyrolysis to store charge between their plates.

 

200. Which among the following is the odd one out in capacitor?

A. Ceramic capacitor
B. Electrolyte capacitor
C. Tuning capacitor
D. Paper capacitor

Answer: C

Ceramic capacitors, electrolyte capacitors, and paper capacitors are fixed capacitors whereas tuning capacitors is a variable capacitors, hence it is the odd one out.

 

201. In a variable capacitor, capacitance can be varied by ______

A. Turning the rotatable plates in or out
B. Sliding the rotatable plates
C. Changing the plates
D. Changing the material of plates

Answer: A

As the plates are rotated, the area of the plates between which the field exists will vary. Capacitance depends on the area, hence as the area varies, the capacitance also varies.

 

202. The simplest kind of capacitor is ________

A. Ceramic capacitor
B. Electrolyte capacitor
C. Tuning capacitor
D. Paper capacitor

Answer: D

The paper capacitor consists of two strips of aluminum foil separated by sheets of waxed paper. This whole setup is rolled up into the form of a cylinder. Since the materials require for its construction are easily available, it is the simplest kind of capacitor.

 

203. Capacitor preferred when there is high frequency in the circuits is _______

A. Electrolyte capacitor
B. Mica capacitor
C. Air capacitor
D. Glass capacitor

Answer: B

Mica capacitors are preferred for high-frequency circuits because they have low ohmic losses and less reactance.

 

204. The type of capacitors used in communication transmitters are?

A. Electrolyte capacitor
B. Variable capacitor
C. Air capacitor
D. Glass capacitor

Answer: B

The variable capacitor is used to tune all the circuits to the same frequency i.e. resonance frequency so they are used in communication transmitters.

 

205. Which capacitors are relatively costly?

A. Electrolyte capacitor
B. Mica capacitor
C. Air capacitor
D. Glass capacitor

Answer: B

Mica capacitors are relatively expensive because it consists either of alternate layers of mica and metal foil clamped tightly together, or of thin films of silver on the two sides of a mica sheet. Silver is an expensive metal, hence mica capacitors are expensive.

 

206. ____________ capacitors usually have a colour code to find its value.

A. Electrolyte capacitor
B. Variable capacitor
C. Polyester capacitor
D. Glass capacitor

Answer: C

Polyester capacitors usually come with a color code because they are very small and their values cannot be printed on their body.

 

207. ______________ capacitors have a high leakage voltage.

A. Electrolyte capacitor
B. Variable capacitor
C. Air capacitor
D. Polyester capacitor

Answer: D

Polyester capacitors can operate at high voltages, that is, a few thousand volts and the leakage resistance is high, that is, usually 100 M.

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