RRB JE Electrical (CBT II) Mock Test- 8 - Electrical Engineering (EE) MCQ

Janapav hill situated near Indore is the source of Chambal River.

Suspended solids refers to small solid particles which remain in suspension in water as a colloid or due to the motion of the water,suspended solids can be removed by the sedimentation because of their comparatively large size. It is used as one indicator of water quality.

The frequency of a series RLC circuit at resonance is,

If the value of all the components doubled, the new frequency will be

Faraday’s first law of electromagnetic induction states that whenever a conductor is placed in a varying magnetic field, emf is induced which is called induced emf. This induced emf is independent of coil resistance.

The name of our planet Earth originates from English language. The name Earth derives from the eighth-century Anglo-Saxon word erda, which means ground or soil. It became eorthe later, and then erthe in Middle English.

The materials used for heating element should have the following properties
1. High specific resistance
2. High melting point
3. Low temperature coefficient of resistance
4. Free from oxidation
5. High mechanical strength
6. Non corrosive
7. Economical

The relative permeability (μ_r) of a substance is the ratio of magnetic permeability (μ) of the substance to the permeability of free space (μ₀)
μ_r = μ/μ₀
Hence, it is a dimensionless quantity and is equal to 1 for vacuum

The maximum potential difference or current that can be supplied by an alternator depends on the following factors.

• Rate of rotation
• Strength of the magnetic field
• Number of turns on the coil

Given that s = 0.04, f = 50 Hz

We know that, rotor current frequency = f_r = sf = 0.08 × 50 = 4 Hz

• Windows 10 Mobile was announced on January 21, 2015, as a mobile operating system for smartphones and tablets running on ARM architecture; Its primary focus is unification with Windows 10
• Debian is a Unix-like operating system composed entirely of free software packaged by a team of volunteers
• Microsoft Disk Operating System is an operating system for x-86 based personal computers.
• Android is a mobile operating system developed by Google

Lokpriya Gopinath Bordoloi International Airport, also known as Guwahati International Airport and formerly as 'Borjhar Airport'.

Norton current is nothing but the short circuit current across the load terminal AB.
By applying superposition theorem
When only voltage source active and another source are inactive

I ₁ = 30/15 = 2 A 
Now consider 10 A current source

I₂ = 10 A
Now consider 5 A current source

I₃ = 5 A
Norton current I_N = I₁ + I₂ + I₃ = 2 + 10 + 5 = 17 A

• Light load adjustment for induction type energy meter is usually done at 5% of full load current.
• In order to recorded true energy by the energy meter during light load, a small shading loop is placed between the shunt magnet and the disc.

• We know that, a current carrying conductor produces its own magnetic field, and this magnetic field affects the main magnetic field of the alternator
• It has two undesirable effects, either it distorts the main field, or it reduces the main field flux or both; They deteriorate the performance of the machine
• When the field gets distorted, it is known as a cross magnetizing effect; In this case, the output will be non-sinusoidal
• Cross-magnetizing effect can be reduced by shifting the brush positions

Central Processing Unit (CPU): It is the most important unit, where all the processing jobs take place. CPU is the control centre of the computer and hence it is said to be the brain of the computer. CPU has three main components:

1. Arithmetic Logic Unit (ALU): It performs all the arithmetic operations like addition (+), multiplication (*), subtraction (-), division (/) on the numerical data directed by the control unit. All the logical operations, like less than (<), greater than (>), equal to (=), not equal to (≠) etc. are also carried out by ALU.
2. Control Unit (CU): It controls and coordinates all the operations taking place in the system. It controls the flow of data and information from one unit to the other.
3. Registers/Memory Unit (MU): To execute a program, data and instructions need to be stored temporarily. This storage is done in the MU. The data and instructions are retrieved from MU by Control Unit for supplying to ALU as when required by the program.

Time graded protection of a redial feeder can be achieved by definite time relays and Inverse time relays
Definite time relays:

• During relay coordination in electrical power system protection scheme, there is some time intentionally required, to operate some specific relays after some specific time delays.
• Definite time lag relays are those which operate after a specific time.

Inverse time relays:
In this type of relays, the time of operation depends upon the magnitude of actuating quantity (current). If the magnitude of actuating quantity is very high, the relay operation is very fast which is shown in below figure

Lightning arrester:

• The device which is used for the protection of the equipment at the substations against travelling waves, such type of device is called lightning arrester or surge diverter
• It diverts the abnormal high voltage to the ground without affecting the continuity of supply
• It is connected between the line and earth, i.e., in parallel with the equipment to be protected at the substation

Characteristics are shown below.

• Water pollution in rivers is measured by the dissolved amount of oxygen
• BOD is used to measure water pollution as higher BOD means a higher amount of water pollution
• If BOD of water is zero, then the water is safe to drink

• Chelsea got the better of its English Premier League rivals to win the Europa League final Wednesday, beating Arsenal 4-1 in the Baku Olympic Stadium.
• Chelsea won their fifth major Uefa European competition final, with only Liverpool winning more among eight English clubs.

A salient pole synchronous motor is running at no load if Its field current is switched off. The motor will Continue to run at synchronous speed due to the presence of reluctance torque.
If the torque equations of salient pole synchronous motor are analysed, there is a term independent on field strength, which is nothing but reluctance torque.

Current through 1Q resistor (using current division) = 2 x 3/3 + 3  = 1 amp
The voltage across 1-ohm branch = V_th = 1 volt
Rth = 1|| 5 = 1 x 5/6 = 5/6 Ω (Replacing current source by its internal impedance i.e. open circuit)

• Split phase induction motors have low starting current and moderate starting torque
• So, these motors are used in fans, blowers, centrifugal pumps, washing machine, grinder, lathes, air conditioning fans, etc.
• These motors are available in the size ranging from 0.05 kW to 0.5 kW

• If a 132-kV line passes over a residential building, the minimum vertical clearance from the roof of the building shall be 4.57 m
• Minimum clearance of HV lines from ground across the streets = 6 m
• Minimum horizontal clearance of a LV line from a residential building = 1.2 m
• Minimum clearance provided for the 132-kV line from the ground = 6.4 m
• Horizontal spacing between phase conductors of 132 kV line = 8 m

Concept:
For star - delta transformation

z _A = z₁+ z₂ + z₁ z₂/ z₃
Application

Equivalent circuit

⇒ Equivalent capacitance
2C/3║C/3 = C 

We know that underdamped galvanometer causes a great waste of time as the coil settles to its final steady position after oscillating about it.

An overdamped galvanometer represents very sluggish behaviour and loss of time.

A critically damped galvanometer represents an arrangement that takes the coil to its final steady position in the minimum time that is possible without overshooting.

The best-operating conditions are attained with a galvanometer that is either critically damped or slightly underdamped which may even give a faster response.

• Nikoloz Basilashvili emerged victorious after a three-set battle with Andrey Rublev to successfully defend his title at the German Tennis Championships.
• The reigning champion claimed his 12th straight win in Hamburg 7-5 4-6 6-3.
• With the win, he has become first player to win the event in successive years since Roger Federer in 2004-2005.