EE MCQ

SSC JE Electrical 2019 with solution SET-2
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For indoor lighting the range of space : height is

In order to achieve uniform illumination over a surface, the number of luminaries must be placed suitably. The space-height ratio plays a vital role in deciding the height of lamps from floor level and their spacing.**Space to height ratio**

It is defined as the ratio of horizontal distance between adjacent lamps to the height of their mountings.

In order to obtain almost uniform illumination over the working plane, the distance between the lamps should not be too much. An ideal scheme could be developed, when there is a large number of small size lamps. But this would increase the installation cost. To have uniform illumination, the ratio of the spacing between the lamps and their height above the working plane (i.e., space-height ratio) should normally lie between 1 and 2.

Related Question

SSC JE Electrical 2019 with solution SET-2
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The number of brushes required for a 4 pole, lap wound DC machine is

**Lap Winding:-**In a lap winding the number of parallel paths (a) is always equal to the number of poles (p) and also to the number of brushes. In the given question number of poles is 4 hence the number of brushes will be 4.**Wave Winding:-** In wave windings, the number of parallel paths (a) is always two and there may be two or more brush positions.

SSC JE Electrical 2019 with solution SET-2
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The 2’s complement of 1010101 is

The 2’s complement of the number (1010101)2 is found in two steps. First, convert the given number into its l’s complement.

1’s complement of a binary number is just an inversion of individual bits.

1’s complement of (1010101)2 is (0101010)2

To find 2’s complement of the number add one to the least significant bit (LSB). So

SSC JE Electrical 2019 with solution SET-2
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The type of insulator used on lines up to 33 kV is?

Pin insulatorReel insulator

Post insulator

Strain insulator

Choose the correct options

Pin insulatorReel insulator

Post insulator

Strain insulator

Choose the correct options

Pin Insulator:- Pin insulators are commonly used on rural and urban primary distribution lines. These can be used up to 33 kV. Pin insulators can be of a single piece or multipiece. The pin type of insulators is uneconomical beyond 33 kV operating voltage. Also, the replacement of these insulators is expensive. For these reasons for insulating overhead lines against higher voltages, suspension insulators are used.

Strain Insulator:- The strain insulators are exactly identical in shape with the suspension insulators. These are used to take the tension of the conductors at line terminals, at angle towers, at road crossings, and at the junction of overhead lines with cables. These insulators are, therefore, known as tension or strain insulators. For low voltage lines (less than 11 kV), shackle insulators are used as strain insulators.

SSC JE Electrical 2019 with solution SET-2
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Two coils are said to be ‘magnetically isolated’ provided the coefficient of coupling K

When there is no mutual flux between two coils, they are said to be magnetically isolated. In this case. k = 0 and M = 0.