Electrical Engineering Practice Impotent Questions Part 7

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73-A lightning arrester connected in the line and earth in a power system:

A. Reflects back travelling waves approaching it

B. Suppress high frequency oscillations in the line

C. Protects transmission line against direct lightning strokes

D. Protects terminal equipment against travelling surge

Ans: C. Protects transmission line against direct lightning strokes

74-Infrequency modulation, noise components which affect the amplitude can be eliminated by using:

A. A differentiator

B. An oscillator

C. An fm limiter circuit

D. A mixer

E. An rf amplifier

Ans: C. An fm limiter circuit

75-Cost of operation of which of the following plants is least?

A. Gas turbine plant

B. Thermal power plant

C. Nuclear power plant

D. Hydroelectric plant

Ans: D. Hydroelectric plant

76-The effect of ice deposition on conductor is

(A) Increased skin effect

(B) reduced corona losses

(C) Increased weight

(D) Reduced sag.

Ans: (C) Increased weight

77-The protection against direct lightening strokes and high voltage steep waves is provided by

(A) Earthing of neutral

(B) Lightening arresters

(C) Ground wires

(D) Lightening arresters and ground wires.

Ans: (D) Lightening arresters and ground wires.

78-The dc compound motors are generally

A. level compound.

B. cumulative compound.

C. differential compound.

D. none of these.

Ans:

79-Air standard efficiency of a diesel engine depends on

(A) Compression ratio

(B) Speed

(C) Fuel

(D) Torque.

Ans: (A) Compression ratio

80-Inpowerplantscoolingtowersareusedto

(A) Cool exhaust steam

(B) Cool repeated steam

(C) Cool feed water

(D) Cool condenser outlet water

Ans: (D) Cool condenser outlet water

81-Skin effect is proportional to

(A) diameter of conductor

(B) (Diameter of conductor)

(C) (Diameter of conductor) 2

(D) (Diameter of conductor) 2

Ans: (Diameter of conductor) 2

82-The capacitor switching is easily done with

A) Air blast circuit breaker

B) Oil circuit breaker

C) Vacuum circuit breaker

D) Any one of these

Ans: C) Vacuum circuit breaker