Q 1. “The surface integral of the normal component of the electric displacement D over any closed surface equals the charge enclosed by the surface”. The above statement is associated with
(A) Gauss’s law
(B) Kirchhoff s law
(C) Faraday’s law
(D) Lenz’s law
Answer: Option A
Q 2. The phenomenon of an uncharged body getting charged merely by the nearness of a charged body is known as
(A) Photoelectric effect
(B) Chemical effect
(C) Magnetic effect
(D) Induction
Answer: Option D
Q 3. 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
Answer: Option D
Q 4. If an ohmmeter reading immediately goes practically to zero and stays there, capacitor is
(A) Charged
(B) Short-circuited
(C) Lossy
(D) Satisfactory
Answer: Option B
Q 5. 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: Option A
Q 6. A condenser suitable for D.C. only is
(A) Metallic plate variable gang condenser
(B) Metallic paper capacitor
(C) Oil impregnated paper condenser
(D) Poled aluminium electrolytic condenser
Answer: Option D
Q 7. Two plates of a parallel plate capacitor after being charged from a constant voltage source are separated apart by means of insulated handles, then the
(A) Voltage across the plates increases
(B) Voltage across the plates decreases
(C) Charge on the capacitor decreases
(D) Charge on the capacitor increases
Answer: Option B
Q 8. Which of the following capacitors will have the least variation?
(A) Paper capacitor
(B) Ceramic capacitor
(C) Silver plated mica capacitor
(D) None of the above
Answer: Option C
Q 9. Air capacitors are generally available in the range
(A) 10 to 400 pF
(B) 1 to 20 pF
(C) 100 to 900 pF
(D) 20 to 100 pF
Answer: Option A
Q 10. While testing a capacitor with ohm meter, if the capacitor shows charging, but the final resistance reading is appreciably less than normal, it can be concluded that the capacitor is
(A) Short-circuited
(B) Open circuited
(C) Alright
(D) Leaky
Answer: Option D
Q 11. A mica capacitor and a ceramic capacitor both have the same physical dimensions. Which will have more value of capacitance?
(A) Ceramic capacitor
(B) Mica capacitor
(C) Both will have identical value of capacitance
(D) It depends on applied voltage
Answer: Option A
Q 12. The units of volume charge density are
(A) Coulomb/meter
(B) Coulomb/meter
(C) Coulomb/meter
(D) Coulomb/meter
Answer: Option C
Q 13. The total deficiency or excess of electrons in a body is known as
(A) Current
(B) Voltage
(C) Potential gradient
(D) Charge
Answer: Option D
Q 14. In a cable capacitor, voltage gradient is maximum at the surface of the
(A) Earth
(B) Conduction
(C) Sheath
(D) Insulator
Answer: Option B
Q 15. The capacitance between two plates increases with
(A) Shorter plate area and higher applied voltage
(B) Shorter plate area and shorter distance between them
(C) Larger plate area, longer distance between plates and higher applied voltage
(D) Larger plate area and shorter distance between plates
Answer: Option D
Q 16. For a good 0.05 uF capacitor ohmmeter reading should
(A) Show low resistance momentarily and back off to a very high resistance
(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: Option A
Q 17. 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: Option D
Q 18. 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: Option C
Q 19. The electric field at a point situated at a distance d from straight charged conductor is
(A) Proportional to d
(B) Inversely proportional to d
(C) Inversely proportional to d
(D) None of the above
Answer: Option B
Q 20. An electrolytic capacitor can be used for
(A) D.C. only
(B) AC. only
(C) Both D.C. as well as A.C.
(D) None of these
Answer: Option A
Q 21. For which of the following parameter variation, the capacitance of the capacitor remains unaffected?
(A) Distance between plates
(B) Area of the plates
(C) Nature of dielectric
(D) Thickness of the plates
Answer: Option D
Q 22. In a capacitive circuit
(A) A steady value of applied voltage causes discharge
(B) An increase in applied voltage makes a capacitor charge
(C) Decrease in applied voltage makes a capacitor charge
(D) None of the above
Answer: Option B
Q 23. The capacitor preferred for high frequency circuits is
(A) Air capacitor
(B) Mica capacitor
(C) Electrolytic capacitor
(D) None of the above
Answer: Option B
Q 24. Which of the following capacitors is marked for polarity?
(A) Air
(B) Paper
(C) Mica
(D) Electrolytic
Answer: Option D
Q 25. Capacitors are used for audio frequency and radio frequency coupling and tuning.
(A) Air
(B) Mica
(C) Plastic film
(D) Ceramic
Answer: Option B
Q 26. At a point may be defined as equal to the lines of force passing normally through a unit cross section at that point.
(A) Electric intensity
(B) Magnetic flux density
(C) Electric flux
(D) None of the above
Answer: Option A
Q 27. The time constant of an R-C circuit is defined as the time during which capacitor charging voltage actually rises to _________ percent of its value.
(A) 37, initial
(B) 62, initial
(C) 62, final
(D) 37, final
Answer: Option C
Q 28. 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: Option B
Q 29. An electrolytic capacitor is generally made to provide
(A) Low capacitance
(B) Fixed capacitance
(C) Variable capacitance
(D) Large value of capacitance
Answer: Option D
Q 30. A field line and an equipotential surface are
(A) Always parallel
(B) Always at 90°
(C) Inclined at any angle 0
(D) None of the above
Answer: Option B
Q 31. For making a capacitor, it is better to select a dielectric having
(A) Low permittivity
(B) High permittivity
(C) Permittivity same as that of air
(D) Permittivity slightly more than that of air
Answer: Option B
Q 32. Which of the following statements is correct?
(A) Air capacitors have a black band to indicate the outside foil
(B) Electrolytic capacitor must be connected in the correct polarity
(C) Ceramic capacitors must be connected in the correct polarity
(D) Mica capacitors are available in capacitance value of 1 to 10 pF
Answer: Option B
Q 33. The sparking between two electrical contacts can be reduced by inserting a
(A) Capacitor in parallel with contacts
(B) Capacitor in series with each contact
(C) Resistance in line
(D) None of the above
Answer: Option A
Q 34. The capacity of capacitor bank used in power factor correction is expressed in terms of
(A) kW
(B) kVA
(C) kVAR
(D) Volts
Answer: Option C
Q 35. Which of the following statements is incorrect?
(A) The thinner the dielectric, the more the capacitance and the lower the voltage breakdown rating for a capacitor. (B) A six dot mica capacitor colour coded white, green, black, red and yellow has the capacitance value of 500 pF (C) Capacitors in series provide less capacitance but a higher voltage breakdown rating for the combination
(D) A capacitor can store charge because it has a dielectric between two conductors
Answer: Option B
Q 36. The potential gradient across the material of low permittivity is than across the material of high permittivity.
(A) Smaller
(B) Greater
(C) Both (A) and (B)
(D) None of the above
Answer: Option B
Q 37. At a point is equal to the negative potential gradient at that point.
(A) Electric intensity
(B) Electric flux
(C) Magnetic flux
(D) Magnetic flux density
Answer: Option A
Q 38. 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: Option C
Q 39. The ohmmeter reading for a short circuited capacitor is
(A) Infinity
(B) Few kilo ohms
(C) Few mega-ohms
(D) Zero
Answer: Option D
Q 40. 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: Option D
Q 41. Which capacitor will be physically smaller for the same ratings?
(A) Ceramic capacitor
(B) Paper capacitor
(C) Both will be of equal size
(D) None of the above
Answer: Option A
Q 42. For closer tolerances which of the following capacitors is usually preferred?
(A) Paper capacitor
(B) Mica capacitor
(C) Ceramic disc capacitor
(D) None of the above
Answer: Option B
Q 43. The inverse of capacitance is called
(A) Reluctance
(B) Conductance
(C) Susceptance
(D) Elastance
Answer: Option D
Q 44. The number of Faraday tubes of flux passing through a surface in an electric field is called
(A) Electric flux
(B) Electric flux density
(C) Magnetic flux density
(D) Electric charge density
Answer: Option A
Q 45. Permittivity is expressed in
(A) Farad/m2
(B) Farad/meter
(C) Weber/meter
(D) Weber/m2
Answer: Option B
Q 46. 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: Option A
Q 47. Dielectric strength of a medium is usually expressed in
(A) J/mm
(B) C/m2
(C) kV/mm
(D) N/mm
Answer: Option C
Q 48. Voltage applied across a ceramic dielectric produces an electrolytic field 100 times greater than air. What will be the value of dielectric constant?
(A) 50
(B) 100
(C) 150
(D) 200
Answer: Option B
Q 49. The direction of electric field due +0 positive charge is.
(A) Away from the charge
(B) Towards the charge
(C) Both (A) and (B)
(D) None of the above
Answer: Option A
Q 50. The capacitance of a capacitor is not affected by
(A) Distance between plates
(B) Area of plates
(C) Thickness of plates
(D) All of the above
Answer: Option C