RRB JE Electrical (CBT II) Mock Test- 10 - Electrical Engineering (EE) MCQ

(R_eq = R x R = R/2)
(and C_eq = CC = 2c)
(T = R_eqC_eq)
(=(R/2) (2C) = RC)

the concentration of H+ ion is the maximum in pH 5.

Synchronous machine has one armature and one rotor. Both are wire wound so both have their own
inductive reactance and resistance.
We can define synchronous impedance as Z_s = X_a + X_r + R_a
X_a = Armature reactance, X_r = Rotor reactance
We are not calculated X_r and R_a as its very low in value and affect is also less
Therefore, we can say that the major component in synchronous impedance of a synchronous
machine is armature reaction reactance.

• The Kailash or Kailasanatha temple is one of the largest rock-cut ancient Hindu temples located in Ellora, Maharashtra.
• A megalith carved out of one single rock, it is considered one of the most remarkable cave temples in India because of its size, architecture and sculptural treatment.
• The Kailasanatha temple (Cave 16) is one of the 32 cave temples and monasteries known collectively as the Ellora Caves.

In forward blocking mode junction J 2 and in reverse blocking mode junction J 1 and J 3 acts as capacitor hence leakage current present in both direction.

• The quantum number defines an electron completely in an atom.
• There are four types of quantum number - Principal Quantum Number, Azimuthal Quantum Number, Magnetic Quantum Number and Spin Quantum Number.
• Principal Quantum Number describes the size, shape and energy of the shell to which an electron belongs whereas Azimuthal Quantum Number determines the shape of the electron cloud and the number of sub-shells in a shell.
• Magnetic Quantum Number determines the orientation of sub-shells whereas the spin quantum number represents the direction of the electron spin.

• Avalanche breakdown occurs when we apply a high reverse voltage across the PN junction
• When we increase the applied reverse voltage across the PN junction, the electric field across the junction will keep increasing
• This electric field exerts a force on the electrons at the junction and it frees them from covalent bonds

The deflecting torque is used for deflection, the controlling torque acts opposite to the deflecting torque. So before coming to rest the pointer always oscillates due to inertia, so to bring the pointer rest within a short time by reducing oscillations, we use damping torque without effecting controlling torque (or) inertia.

The following mechanism can be used for producing damping torque.

1. Air friction damping

2. Fluid friction damping

An ideal transformer a transformer which has no copper losses, no iron loss in core and no leakage flux. In other words, an ideal transformer gives output power exactly equal to the input power.

Characteristics of an ideal transformer:

• The resistances of primary and secondary winding are zero
• The core of the ideal transformer has infinite permeability
• The leakage flux in the transformer core is zero
• The ideal transformer has 100 percent efficiency

• The electric field formed in the depletion region acts as a barrier
• This barrier is formed when some of the free electrons in the n-region diffuse across the junction and combine with holes to form negative ions
• The development of barrier potential in the depletion zone of a PN junction is consequent to diffusion of majority carriers across the junction

If f is the frequency in Hz, n_s the synchronous speed in rps, and p is the number of pairs of poles, the relation between f, n_s and p for a three-phase machine is:

f = n_s p/120

Electric railway can handle the traffic up to double the amount possible with steam railway. It is because of large passenger carrying capacity and higher schedule speed of electric locomotives compared to steam railway.

Electric railway has better speed control compared to steam railways, but it is not the factor for handling high traffic.

• Electrical power is measured with a wattmeter. A wattmeter consists of a current coil connected in series with load, while the other potential coil is connected parallel with load
• Two wattmeter method is generally adopted to measure the power in a three-phase and 3 wire imbalanced load system.
• If the three phase systems are 3-phase 4 wire (neutral) then one may use three watt-meters connected and add all to get the sum.

• When a high voltage is applied across an air gap, the air in the gap gets ionized under the influence of electrostatic forces and becomes conducting medium.
• Current flows in the form of a continuous spark, called the arc.
• It is to be noted that a very high voltage is required to establish an arc across an air gap but to maintain an arc small voltage may be sufficient.

During balance load total power P = 3 × 100 = 300 W

If the lamp in one of the phases goes off, then total power = 300 × 0.57 = 171 W

When two capacitors C₁ and C₂ are connected in series then total capacitance = C₁ x C₂/ C₁+ C₂
Ceq 5 x 10 = 50/15 = 3.33  µf 
Total charge = Q = CV = 3.33 × 300 = 1000 µC

• A macro virus is a virus that is written in a macro language: a programming language which is embedded inside a software application (word processors)
• It is a malicious code that installs in the memory and then infects future programs
• An interrupt is a signal to the processor emitted by hardware or software indicating an event that needs immediate attention
• Trojan is a malicious computer program which misleads users of its true intent

The armature resistances are: 0.4 ohms and 1.2 ohm

For the same voltage rating, machine A will have more parallel paths than machine B as machine A has less resistance.

For 1440 rpm the number of poles should be = 4
If the machine runs at 850 rpm at 30 Hz, then synchronous speed will be
N _s = 120 x f/p = 120 x 30/4 = 900 r pm
Slip = N _s -  N _r /N _s = 900 - 850/900 = 50/900 = 0.0556

• Each worksheet is made up of cells and cells are a result of the intersection of rows and columns
• They are basic units for storing data
• Each cell gets its name from this intersection
• The address of a cell that is in column A and has its row number as 4 is referred to as cell A4
• Thus the letter and number of the intersecting column and row is the cell address
• A group of contiguous cells is called a range
• An example of a cell range would be G1: G3

Cell address of 4^th row and 4^th column is D4

In series RLC Circuit we have phase difference Ø = tan ^-1 ω L/R
Hence as R decreases then ω L/R values increases hence the phase difference also increases.

• The internet is a globally connected network system that transmits data via various types of media. Sometimes it is referred to as a ‘network of networks’
• The World Wide Web, or simply web, is a way of accessing information over the medium of the internet
• A web browser is a software application for accessing information on the World Wide Web

The order of waste management hierarchy, from most to least favoured is:
Prevention-Reuse-Recycle-Recovery-Disposal

Prevention: Preventing and reducing waste generation.
Reuse: Giving the products a second life before they become waste.
Recycle: Any recovery operation by which waste materials are reprocessed into products, materials or substances whether for the original or other purposes
Recovery: Some waste incineration based on a political non-scientific formula that upgrades the less inefficient incinerators.
Disposal: Different processes to dispose of the waste are landfilling, incineration, pyrolysis, gasification and other finalist solutions.

AC series motors are also known as the modified DC series motor as their construction is very similar to that of the DC series motor. If a DC series motor is operated on AC supply,

• An AC supply will produce a unidirectional torque because the direction of both the currents (i.e. armature current and field current) reverses at the same time
• Due to the presence of alternating current, eddy currents are induced in the yoke and field cores which results in excessive heating of the yoke and field cores
• Due to the high inductance of the field and the armature circuit, the power factor would become very low
• There is sparking at the brushes of the DC series motor
• It has poor efficiency

• The 20th Anniversary of Kargil Vijay Diwas was celebrated on 26 July 2019.
• The day is named after the successful Operation Vijay in 1999, when India regained the control of the high outposts which had been stealthily taken over by Pakistan.
• The celebrations of 20th Anniversary of Kargil Vijay Diwas began in Delhi on 14 July 2019.

Plant capacity factor: It is the ratio of the average demand on the station and the maximum installed capacity of the station

Load factor: The ratio of average load to the maximum demand during a given period is known as the load factor.

Reserve capacity: It is the difference between plant capacity and maximum demand

If plant capacity is equal to maximum demand, then the load factor is equal to the capacity factor.

If the load factor and capacity factor are equal, it indicates zero reserve capacity. The difference between load factor and capacity factor is the indication of reserve capacity.

Let the value of each resistance is R.|
When four resistors are connected in series, equivalent resistance is given by
R_eq = 4R
Let the supply voltage is V.
The power dissipated in this case is given by,
P1 = V²/Req = V²/4R = 25 
V²/R = 100
When four resistors are connected in parallel, equivalent resistance is given by
R_eq = R/4
The power dissipated in this case is given by,