EE MCQ

SSC JE Electrical 2019 with solution SET-2
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The conductor tied between two supports takes the shape of a ‘catenary’ due to ____?

The difference in level between points of supports and the lowest point on the conductor is called sag.

When the conductor is suspended between two supports at some level, it takes the shape of a catenary. However, if the sag is very small compared with the span, then the sag-span curve is like a parabola.

The tension at any point on the conductor acts tangentially. Thus tension To at the lowest point O acts horizontally.

Related Question

SSC JE Electrical 2019 with solution SET-2
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____ Lamps are used to light up sports stadiums?

The most common type of floodlight is the metal-halide lamp, which emits a bright white light (typically 75-100 lumens/Watt). Sodium-vapor lamps are also commonly used for sporting events because they imitate daylight conditions, and colors appear natural.

They have a very high lumen-to-watt ratio (typically 80-140 lumens/Watt), making them a cost-effective choice when certain lux levels must be provided.

SSC JE Electrical 2019 with solution SET-2
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While estimating the overhead lines, if the number of poles required is 14, then what is the estimated number of earth sets required?

While estimating the overhead lines, the first and last pole is always earth connected and after every 3rd electrical pole, the fourth pole is earthed. Therefore, the approximate number of required ground set = 4

SSC JE Electrical 2019 with solution SET-2
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In the salient pole of the phase synchronous machine, the rotor will have

The rotor of the synchronous machine carries a field winding that is supplied with d.c. through two slip rings by a separate d.c. source. Synchronous Rotor construction is of two types, namely :

Salient (or projections) pole type.

Cylindrical type (or non-salient pole type)**Salient-pole rotor:**-

In this type, salient poles are mounted on a large circular steel frame which is fixed to the shaft of the alternator.

The rotors of salient-pole rotor machines have concentrated winding on the poles and a nonuniform air gap.

Salient pole generators have a large number of poles. sometimes as many as 50, and operate at lower speeds.

The synchronous generators in hydroelectric power stations are of the salient pole type and are driven by water turbines.

The rotors are shorter axial length but have a large diameter.

SSC JE Electrical 2019 with solution SET-2
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If the AC voltage and current are given by the following expressions?

v = 200sin (314t — 60°)

i = 50sin (720t), then what is the phase relation between them?

v = 200sin (314t — 60°)

i = 50sin (720t), then what is the phase relation between them?

When two alternating quantities of the same frequency have different zero points, they are said to have a phase difference. The angle between zero points is the angle of phase difference φ.

In the above-given question, the frequency of voltage and current is different so we can’t calculate the phase difference between them