1) Which is having higher breakdown strength? a. Solid dielectrics b. Liquid dielectrics c. Gases dielectrics d. Equal in all
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2) Within dielectric, an electron starting from the cathode will drift towards the anode and during this motion a. Gains energy from the field and loses during collision b. Gains energy during both motion and collision c. Loses energy during both motion and collision d. Loses energy from the field and gains during collision
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3) The thermal breakdown stresses are a. Lower under ac conditions than under dc condition b. Greater under ac condition than dc condition c. Equal in both condition d. None of these
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4) The spreading of spark channels during tracking, in the form of the branches of a tree is called a. Bunching b. Treeing c. sparking d. none of these
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5) Insulation is necessary for the protection of equipment. Insulation is not necessary between a. Coils and earth b. Coils of different phases c. Turns in a coil d. None of these
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6) The temperature limit for class F insulation is a. 105°C b. 120°C c. 130°C d. 155°C
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7) Insulation of dry type transformers is done using prepregs. It is manufactured by using a. Glass fibres b. Nomex c. Aramide papers d. All of these
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8) For insulators and bushings of power transformers, circuit breakers and instrument transformers, the suitable materials is a. Epoxy resin b. Polyesters resins c. Porcelain d. Silicon rubber
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9) In the half wave rectifier, charging current can be limited by using an additional a. Resistance in series with the secondary of the transformer b. Inductance in series with the primary of the transformer c. Inductance in series with the primary of the transformer d. Capacitance in series with the secondary of the transformer
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10) The ripple voltage for half wave rectifier is a. Smaller than that of full wave rectifier b. Larger than that of full wave rectifier c. Equal to that of full wave rectifier d. None of these
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