EE MCQ

SSC JE Electrical 2019 with solution SET-2
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If the connected light load in a house is 3000W and power sub-circuit load 6000W, then what is the total number of sub-circuits required?

Indian Electricity Rules specify that the maximum load on a light/fan sub-circuit should not exceed 800 watts and the number of points should be limited to 10.

Hence for light load number of sub-circuit = 3000/800 = 3.75 = 4

Indian Electricity Rules specify that the maximum load on a power sub-circuit should not exceed 3000 watts and the number of outlets should be limited to two.

For the power sub-circuit load number of sub-circuit = 6000/3000 = 2

Total subcircuit = 4 + 2 = 6

Related Question

SSC JE Electrical 2019 with solution SET-2
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Observe the given figure. Find Thevenin’s resistance as seen from open-circuited terminals?

To find the Thevenin’s resistance the current source is open-circuited and the voltage source is short-circuited.

SSC JE Electrical 2019 with solution SET-2
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In an alternator, if α = 60°, then find the pitch factor?

The factor by which, the induced E.M.F gets reduced due to short pitching is called pitch factor or coil span factor denoted by Kc. It is given as

Kc = cosα/2

given

α = 60°

Kc = cos60/2

Kc = cos30°

Kc = √3/2

SSC JE Electrical 2019 with solution SET-2
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The number of valence electrons of P and Si are respectively?

Phosphorus (P) has 15 electron i.e 2,8,5. Hence the number of electron in its outermost orbit is 5.

Silicon (Si) has 14 electron i.e 2,8,4. Hence the number of electrons in its outermost orbit is 4.

SSC JE Electrical 2019 with solution SET-2
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For a three-phase induction motor slip at No Load ÷ slip at Full Load

In terms of slip, the actual speed of the motor (N) can be expressed as

N = Ns(1 − s)

At start, the motor is at rest and hence its speed N is zero.

s = 1 ( start)

This is the maximum value of slip s possible for the induction motor which occurs at start. While s = 0 gives us N = N. which is not possible for an induction motor. So slip of the induction motor cannot be zero under any circumstances.

Practically motor operates in the slip range of 0.01 to 0.05 i.e. 1 % to 5 %. The slip corresponding to the full load speed of the motor is called full load slip.

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.