101. The time constant and R-C circuit may also be defined as the time during which the charging current falls to ______ percent of its initial maximum value,
(a) 37
(b) 42
(c) 63
(d) 73
Ans: a
102. The capacitance of a capacitor is influenced by
(a) plate area
(b) plate separation
(c) nature of dielectric
(d) none of the above
(e) all of the above
Ans:
103. A capacitor consists of two
(a) ceramic plates and one mica disc
(b) insulators separated by a dielectric
(c) silver-coated insulators
(d) conductors separated by an insulator
Ans: d
104. Permittivity is expressed in
(a) Farad/sq-m
(b) Farad/metre
(c) Weber/metre
(d) Weber/sq-m
Ans: b
105. Dielectric strength of a material depends on
(a) moisture content
(b) temperature
(c) thickness
(d) all of the above
(e) none of the above
Ans: d
106. 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
Ans: c
107. Which medium has the least dielectric strength ?
(a) Paraffin wax
(b) Quartz
(c) Glass
(d) Air
Ans: d
108. 1 volt/metre is same as
(a) 1 metre/coulomb
(6) 1 newton metre
(c) 1 newton/metre
(d) 1 joule/coulomb
Ans: c
109. One volt is the same as
(a) one joule/coulomb
(b) one coulomb/joule
(c) one coulomb
(d) one joule
Ans: a
110. The capacitance between two plates increases with
(a) shorter plate area and higher ap¬plied voltage
(6) 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
Ans: d
111. 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
Ans: c
112. 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
Ans: c
113. If an ohmmeter reading immediately goes practically to zero and stays there, capacitor is
(a) charged
(b) short-circuited
(c) lossy
(d) satisfactory
Ans: b
114. 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
Ans: c
115. An uncharged conductor is placed near a charged conductor, then
(a) the uncharged conductor gets charged by conduction
(6) 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
Ans: b
116. The presence of an uncharged conductor near a charged one increases the
(a) charge of the charged conductor
(6) capacity of the charged conductor
(c) potential of the charged conductor
(d) all of the above
Ans: b
117. Paper condenser is
(a) always polarised
(6) usually of fixed value
(c) electrolytic condenser
(d) a variable condenser
Ans: b
118. Mica capacitors are characterised by all of thte following except
(a) stable operation
(b) accurate value
(c) low leakage reactance
(d) low losses
Ans: c
119. 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
Ans: a
120. For a good 0.05 uF capacitor ohmmeter reading should
(a) show low resistance momentarily and back off to a very high resis¬tance
(6) 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
Ans: a
121. The ohmmeter reading for a short circuited capacitor is
(a) infinity
(b) few kilo ohms
(c) few megaahms
(d) zero
Ans: d
122. 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
Ans: c
123. Which of the following capacitors preferred for high frequency circuits ?
(a) Air capacitor
(b) Electrolytic capacitor
(c) Mica capacitor
(d) none of the above
Ans: c
124. An electrolytic capacitor is generally made to provide
(a) low capacitance
(b) fixed capacitance
(c) variable capacitance
(d) large value of capacitance
Ans: d
125. In order to remove static electricity from machinery
(a) construct insulated cabins
(b) insulate the machinery
(c) ground the framework
(d) humidify the surroundings
Ans: c
126. 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
Ans: b
127. 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
Ans: a
128. The minimum value of potential gradient in a cable occurs in
(a) insulation
(b) conductor
(c) outer sheath
(d) uniformly all over
Ans: a
129. 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
Ans: d
130. 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
Ans: b
131. Dielectric strength of a medium is usually expressed in
(a) J/mm
(b) C/m2
(c) kV/mm
(d) N/mm
Ans: c
132. 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
Ans: d
133. Which is the most superior dielectric out of the following ?
(a) Air
(b) Glass
(c) Bakelite
(d) Paper
Ans: c
134. When a dielectric is placed in an electric field the field strength
(a) decreases
(b) increases
(c) reduces to zero
(d) remain unchanged
Ans: a
135. 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
Ans: b
136. 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
Ans: c
137. A capacitance is a circuit component that opposes the change in circuit
(a) current
(b) voltage
(c) impedance
(d) none of the above
Ans: a
138. 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
Ans: d
139. 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
Ans: b
Read More Questions:
Electrostatics MCQs Part1
(a) 37
(b) 42
(c) 63
(d) 73
Ans: a
102. The capacitance of a capacitor is influenced by
(a) plate area
(b) plate separation
(c) nature of dielectric
(d) none of the above
(e) all of the above
Ans:
103. A capacitor consists of two
(a) ceramic plates and one mica disc
(b) insulators separated by a dielectric
(c) silver-coated insulators
(d) conductors separated by an insulator
Ans: d
104. Permittivity is expressed in
(a) Farad/sq-m
(b) Farad/metre
(c) Weber/metre
(d) Weber/sq-m
Ans: b
105. Dielectric strength of a material depends on
(a) moisture content
(b) temperature
(c) thickness
(d) all of the above
(e) none of the above
Ans: d
106. 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
Ans: c
107. Which medium has the least dielectric strength ?
(a) Paraffin wax
(b) Quartz
(c) Glass
(d) Air
Ans: d
108. 1 volt/metre is same as
(a) 1 metre/coulomb
(6) 1 newton metre
(c) 1 newton/metre
(d) 1 joule/coulomb
Ans: c
109. One volt is the same as
(a) one joule/coulomb
(b) one coulomb/joule
(c) one coulomb
(d) one joule
Ans: a
110. The capacitance between two plates increases with
(a) shorter plate area and higher ap¬plied voltage
(6) 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
Ans: d
111. 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
Ans: c
112. 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
Ans: c
113. If an ohmmeter reading immediately goes practically to zero and stays there, capacitor is
(a) charged
(b) short-circuited
(c) lossy
(d) satisfactory
Ans: b
114. 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
Ans: c
115. An uncharged conductor is placed near a charged conductor, then
(a) the uncharged conductor gets charged by conduction
(6) 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
Ans: b
116. The presence of an uncharged conductor near a charged one increases the
(a) charge of the charged conductor
(6) capacity of the charged conductor
(c) potential of the charged conductor
(d) all of the above
Ans: b
117. Paper condenser is
(a) always polarised
(6) usually of fixed value
(c) electrolytic condenser
(d) a variable condenser
Ans: b
118. Mica capacitors are characterised by all of thte following except
(a) stable operation
(b) accurate value
(c) low leakage reactance
(d) low losses
Ans: c
119. 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
Ans: a
120. For a good 0.05 uF capacitor ohmmeter reading should
(a) show low resistance momentarily and back off to a very high resis¬tance
(6) 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
Ans: a
121. The ohmmeter reading for a short circuited capacitor is
(a) infinity
(b) few kilo ohms
(c) few megaahms
(d) zero
Ans: d
122. 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
Ans: c
123. Which of the following capacitors preferred for high frequency circuits ?
(a) Air capacitor
(b) Electrolytic capacitor
(c) Mica capacitor
(d) none of the above
Ans: c
124. An electrolytic capacitor is generally made to provide
(a) low capacitance
(b) fixed capacitance
(c) variable capacitance
(d) large value of capacitance
Ans: d
125. In order to remove static electricity from machinery
(a) construct insulated cabins
(b) insulate the machinery
(c) ground the framework
(d) humidify the surroundings
Ans: c
126. 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
Ans: b
127. 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
Ans: a
128. The minimum value of potential gradient in a cable occurs in
(a) insulation
(b) conductor
(c) outer sheath
(d) uniformly all over
Ans: a
129. 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
Ans: d
130. 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
Ans: b
131. Dielectric strength of a medium is usually expressed in
(a) J/mm
(b) C/m2
(c) kV/mm
(d) N/mm
Ans: c
132. 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
Ans: d
133. Which is the most superior dielectric out of the following ?
(a) Air
(b) Glass
(c) Bakelite
(d) Paper
Ans: c
134. When a dielectric is placed in an electric field the field strength
(a) decreases
(b) increases
(c) reduces to zero
(d) remain unchanged
Ans: a
135. 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
Ans: b
136. 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
Ans: c
137. A capacitance is a circuit component that opposes the change in circuit
(a) current
(b) voltage
(c) impedance
(d) none of the above
Ans: a
138. 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
Ans: d
139. 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
Ans: b
Read More Questions:
Electrostatics MCQs Part1
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