McqMate
Chapters
| 101. |
Permittivity is expressed in |
| A. | Farad/sq-m |
| B. | Farad/metre |
| C. | Weber/metre |
| D. | Weber/sq-m |
| Answer» B. Farad/metre | |
| 102. |
Dielectric strength of a material depends on |
| A. | moisture content |
| B. | temperature |
| C. | thickness |
| D. | all of the above |
| Answer» D. all of the above | |
| 103. |
What will happen to an insulating medium if voltage more than the breakdown voltage is applied on it ? |
| A. | It will become magnetic |
| B. | It will melt |
| C. | It will get punctured or cracked |
| D. | Its molecular structure will get changed |
| Answer» C. It will get punctured or cracked | |
| 104. |
Which medium has the least dielectric strength ? |
| A. | Paraffin wax |
| B. | Quartz |
| C. | Glass |
| D. | Air |
| Answer» D. Air | |
| 105. |
1 volt/metre is same as |
| A. | 1 metre/coulomb |
| B. | 1 newton metre |
| C. | 1 newton/metre |
| D. | 1 joule/coulomb |
| Answer» C. 1 newton/metre | |
| 106. |
One volt is the same as |
| A. | one joule/coulomb |
| B. | one coulomb/joule |
| C. | one coulomb |
| D. | one joule |
| Answer» A. one joule/coulomb | |
| 107. |
The capacitance between two plates increases with |
| A. | shorter plate area and higher ap¬plied voltage |
| B. | shorter plate area and shorter dis¬tance between them |
| C. | larger plate area, longer distance between plates and higher,applied voltage |
| D. | larger plate area and shorter distance between plates |
| Answer» D. larger plate area and shorter distance between plates | |
| 108. |
The capacitance C is charged through a resistance R. The time constant of the charging circuit is given by |
| A. | CIR |
| B. | 1/RC |
| C. | RC |
| D. | RIC |
| Answer» C. RC | |
| 109. |
The bridge used for the measurement of the value of the capacitance is |
| A. | Wien's bridge |
| B. | Wheatstone bridge |
| C. | Schering bridge |
| D. | Hay's bridge |
| Answer» C. Schering bridge | |
| 110. |
If an ohmmeter reading immediately goes practically to zero and stays there, capacitor is |
| A. | charged |
| B. | short-circuited |
| C. | lossy |
| D. | satisfactory |
| Answer» B. short-circuited | |
| 111. |
Out of the following capacitors of identical rating which one will have the smallest dimensions ? |
| A. | Aluminium foil capacitor |
| B. | Mica capacitor |
| C. | Ceramic capacitor |
| D. | Paper capacitor |
| Answer» C. Ceramic capacitor | |
| 112. |
An uncharged conductor is placed near a charged conductor, then |
| 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 such |
| Answer» B. the uncharged conductor gets charged by induction and then attracted towards the charging body | |
| 113. |
The presence of an uncharged conductor near a charged one increases the |
| A. | charge of the charged conductor |
| B. | capacity of the charged conductor |
| C. | potential of the charged conductor |
| D. | all of the above |
| Answer» B. capacity of the charged conductor | |
| 114. |
Paper condenser is |
| A. | always polarised |
| B. | usually of fixed value |
| C. | electrolytic condenser |
| D. | a variable condenser |
| Answer» B. usually of fixed value | |
| 115. |
Mica capacitors are characterised by all of thte following except |
| A. | stable operation |
| B. | accurate value |
| C. | low leakage reactance |
| D. | low losses |
| Answer» C. low leakage reactance | |
| 116. |
A potential of 400 V is applied to a capacitor, the plates of which are 4 mm apart. The strength of electric field is |
| A. | 100 kV/m |
| B. | 10 kV/m |
| C. | 5 kV/m |
| D. | 2 kV/m |
| Answer» A. 100 kV/m | |
| 117. |
For a good 0.05 uF capacitor ohmmeter reading should |
| A. | show low resistance momentarily and back off to a very high resis¬tance |
| B. | show high resistance momentarily and then a very low resistance |
| C. | go quickly to 50 ohm approximately and remain there |
| D. | not move at all |
| Answer» A. show low resistance momentarily and back off to a very high resis¬tance | |
| 118. |
The ohmmeter reading for a short circuited capacitor is |
| A. | infinity |
| B. | few kilo ohms |
| C. | few megaahms |
| D. | zero |
| Answer» D. zero | |
| 119. |
Which of the following statements is correct ? |
| A. | Mica capacitors are available in capacitance values of 5 to 20 \iF |
| B. | Air capapitors have a black band to indicate the outside foil |
| C. | Electrolytic capacitors must be connected in correct polarity |
| D. | Ceramic capacitors must be con¬nected in correct polarity |
| Answer» C. Electrolytic capacitors must be connected in correct polarity | |
| 120. |
Which of the following capacitors preferred for high frequency circuits ? |
| A. | Air capacitor |
| B. | Electrolytic capacitor |
| C. | Mica capacitor |
| D. | none of the above |
| Answer» C. Mica capacitor | |
| 121. |
An electrolytic capacitor is generally made to provide |
| A. | low capacitance |
| B. | fixed capacitance |
| C. | variable capacitance |
| D. | large value of capacitance |
| Answer» D. large value of capacitance | |
| 122. |
In order to remove static electricity from machinery |
| A. | construct insulated cabins |
| B. | insulate the machinery |
| C. | ground the framework |
| D. | humidify the surroundings |
| Answer» C. ground the framework | |
| 123. |
If a third equal and similar charge is placed between two equal and similar charges, then this third charge will |
| A. | move out of the field of influence of the two charges |
| B. | remain in stable equilibrium |
| C. | not be in equilibrium |
| D. | be in unstable equilibrium |
| Answer» B. remain in stable equilibrium | |
| 124. |
A region around a stationary electric charge has |
| A. | an electric field |
| B. | a magnetic field |
| C. | both (a) and (b) |
| D. | none of the above |
| Answer» A. an electric field | |
| 125. |
The minimum value of potential gradient in a cable occurs in |
| A. | insulation |
| B. | conductor |
| C. | outer sheath |
| D. | uniformly all over |
| Answer» A. insulation | |
| 126. |
Dielectric strength of medium |
| A. | increases with rise in temperature |
| B. | increases with moisture content |
| C. | is same for all insulating materials |
| D. | none of the above |
| Answer» D. none of the above | |
| 127. |
Acharge which when placed in vacuum from an equal and similar charge repels with a force of 9 x 10 N, is known as |
| A. | milli-coulomb |
| B. | micro-coulomb |
| C. | pico-coulomb |
| D. | coulomb |
| Answer» B. micro-coulomb | |
| 128. |
Dielectric strength of a medium is usually expressed in |
| A. | J/mm |
| B. | C/m2 |
| C. | kV/mm |
| D. | N/mm |
| Answer» C. kV/mm | |
| 129. |
A positive and a negative charge are initially 50 mm apart. When they are moved close together so that they are now only 10 mm apart, the force between them will be |
| A. | 5 times smaller than before |
| B. | 5 times greater than before |
| C. | 10 times greater than before |
| D. | 25 times larger than before |
| Answer» D. 25 times larger than before | |
| 130. |
Which is the most superior dielectric out of the following ? |
| A. | Air |
| B. | Glass |
| C. | Bakelite |
| D. | Paper |
| Answer» C. Bakelite | |
| 131. |
When a dielectric is placed in an electric field the field strength |
| A. | decreases |
| B. | increases |
| C. | reduces to zero |
| D. | remain unchanged |
| Answer» A. decreases | |
| 132. |
To prevent the generation of static charges on rubber or flat leather |
| A. | surface is moistened |
| B. | conductive dressing is done |
| C. | oil compound dressing is done |
| D. | talcum powder is sprayed on the surface |
| Answer» B. conductive dressing is done | |
| 133. |
Which of the following capacitor is preferred in case of single phase motor ? |
| A. | Mica capacitor |
| B. | Paper capacitor |
| C. | Electrolytic capacitor |
| D. | Ceramic capacitor |
| Answer» C. Electrolytic capacitor | |
| 134. |
A capacitance is a circuit component that opposes the change in circuit |
| A. | current |
| B. | voltage |
| C. | impedance |
| D. | none of the above |
| Answer» B. voltage | |
| 135. |
A condenser suitable for D.C. only is |
| A. | metallic plate variable gang condenser |
| B. | metallic paper capacitor |
| C. | oil impregrated paper condenser |
| D. | poled aluminium electrolytic condenser |
| Answer» D. poled aluminium electrolytic condenser | |
| 136. |
In a capacitor, the electric charge is stored in |
| A. | metal plates |
| B. | dielectric |
| C. | dielectric as well as metal plates |
| D. | none of the above |
| Answer» B. dielectric | |
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