RRB JE ECE (CBT II) Mock Test- 4 - Electronics and Communication Engineering (ECE) MCQ

A computer Virus is a malicious software that, when executed replicates itself by modifying other computer programs.

Data communications are the exchange of data between two devices via some form of transmission medium such as a wire cable. For data communications to occur the communicating devices must be part of a communication system made up of a combination of hardware (physical equipment) and software (programs).

I = I_Z + I_L
I_max = I_Z + I_Lmax

(30- 5.8) mA = 0.5 mA + I_Lmax
∴ I_Lmax = 23.7 mA

• Burzail Pass connects the Kashmir valley with Deosai Plains of Ladakh.
• It remains covered in snow during the winter.

In telecommunications, a repeater is an electronic device that receives a signal and retransmits it. Repeaters are used to extend transmissions so that the signal can cover longer distances or be received on the other side of an obstruction.

Minimum dimension of copper earth plate = 60 cm × 60 cm × 3.18 mm

Minimum dimension of G.I earth plate = 60 cm × 60 cm × 6.38 mm

When the quantity of acids in the raining water is more than the average, then such rain is called 'Acid
rain'.
We are aware that normally rainwater has a pH of 5.6. When the pH of the rainwater drops below
5.6, it is called acid rain.
Acid rain refers to the ways in which acid from the atmosphere is deposited on the earth's surface.
Oxides of nitrogen and sulphur which are acidic in nature can be blown by wind along with solid
particles in the atmosphere and finally settle down either on the ground as dry deposition or in water,
fog and snow as wet deposition.
Acid rain is a byproduct of a variety of human activities that emit the oxides of sulphur and nitrogen in
the atmosphere. As mentioned earlier, burning of fossil fuels (which contain sulphur and nitrogenous
matter) such as coal and oil in power stations and furnaces or petrol and diesel in motor engines
produce sulphur dioxide and nitrogen oxides.
SO₂ and NO₂ after oxidation and reaction with water are major contributors to acid rain because
polluted air usually contains particulate matter that catalyses the oxidation. 
2SO₂ (g) + O₂ (g) + 2H₂O (I) - 2H₂SO₄ (aq)
4NO₂ (g) + O₂ (g)+ 2H₂O (I) - 4HNO₃ (aq)
The bad effects of acid rain

• When acid rain falls and flows as groundwater to reach rivers, lakes etc, it affects plants and
  animal life in the aquatic ecosystem
• Acid rain is harmful to agriculture, trees and plants as it dissolves and washes away nutrients
  needed for their growth
• It causes respiratory ailments in human beings and animal
• It may also cause corrosion in many buildings bridges, monuments, fencing etc
• It causes irritation in the eyes and skin of human beings
• It causes irritation in the eyes and skin of human beings
• This rain reduces the lustre of the metals too
• Acid rain damages buildings and other structures made of stone or metal
• The Taj Mahal in India has been affected by acid rain 

Clamp-on type and split-core type CTs measure the current in a heavy-current conductor or bus-bar without breaking the current circuit

The split core of the CT along with the secondary winding is simply clamped around the main conductor, which acts as the primary winding of the CT

When used with range selectable shunts and a calibrated ammeter, clam on type CTs can be very conveniently used for direct and quick measurement of current

Vice President of India, Shri M. Venkaiah Naidu released a book titled Vivekadeepini.

It was initially written by Adi Shankaracharya who is one of India’s greatest spiritual and literary geniuses.

Vivekadeepini is a summary of Prashnottara Ratnamalika written by Adi Shankaracharya.

It contains universal truths and are the starting point for reflection.

Indian Army, Navy and Air Force held joint exercise Bull Strike at Teressa Island in Andaman and Nicobar.

The objective was to enhance their coordination in dealing with major security challenges and also to showcase joint operation capability of the three forces.

170 troops from all three services participated and carried out para drop operations in a Combat Free Fall and Static Line mode.

The diffusion length is related to carrier lifetime by the relation
L_n = 
Calculation:
Ln₁/Ln_{2 =} 
Ln₁/Ln₂ =  = 1/√4 = 1/2
Ln₂ = 2 Ln₁

There are different allotropes of carbon:
1. Graphite
2. Diamond
3. Buckminsterfullerene (C60)
The allotrope defines the basic structural arrangement of carbon atoms in a lattice.

The trick to solves this question is to calculate the number of moles of each compound and then multiply by the number of atoms present in 1 unit of a compound.
Application of Concept:
18 g of H₂O
moles of H₂O = 18/2+16 = 1 mole
1 unit of H₂O contains 3 atoms
1 mole of H₂O contains 3 moles of atoms
18 g of O₂
moles of O₂ = 18/32 = 9/16
1 mole of O₂ contains 2 atoms
9/16 moles of O₂ contains 18/16 = 1.125 moles of atoms.
18 g of CO₂
moles of CO₂ = 18/12+332 = 0. 409 moles
1 mole of CO₂ contains 3 atoms
0.409 mole contains 1.227 moles of atoms
18 g of CH₄
moles of CH₄ = 18/12+4 = 1.125 moles
1 mole of CH₄ contains 5 atoms
1.125 moles of CH₄ contains 5.625 moles of atoms
Hence 18 g of methane contains the maximum number of atoms

FIFO (first-in-first-out) algorithm executes first the job that first entered the queue.
A stack is a container of objects that are inserted and removed according to the last-in-first-out (LIFO) principle.
A queue is a container of objects that are inserted and removed according to the first-in-first-out (FIFO) principle.
Hence, the correct option is (B)

Here, we need to find the time that will take to cross 91 km stones completely. 

Given that, in 1 hr. train travels 60 km i.e. 60 km is travelled in 60 min.

This means in 1 minute 1 km is travelled. 

Therefore, 90 km is travelled in 90 minutes i.e. 1 hour 30 minutes 

And the remaining 1 km in 12 seconds. 

Thus, the total time taken is 1 hr. 30 min. 12 sec. 
Hence, the correct option is (B)

Prism can be used for multiplexing and demultiplexing of signals in wavelength Division multiplexing The process is shown in the figure

Hence, the correct option is (A)

Modulation:

Modulation is a process of converting low-frequency signal (Audio frequency AF) with the High-frequency signal (Radio frequency RF) for better transmission and reducing the height of antenna (λ /4) required for transmission.

Demodulation:

An ideal ammeter should have zero internal resistance and a practical ammeter has very low resistance. The shunt multiplier used for ammeter should be very low value resistance.

An ideal voltmeter should have infinite internal resistance and a practical voltmeter has very high resistance. The series multiplier used for voltmeter should be very high value resistance

Electronic Voltmeter:

• The voltmeter which uses the amplifier for increases their sensitivity is known as the electronic voltmeter.
• It is used for measuring the voltages of both the AC and DC devices.
• The electronic voltmeter gives the accurate reading because it has high input resistance.
• An electronic voltmeter draws negligible current from the source because it has high input resistance.

A strain gauge is a sensor whose resistance varies with applied force.

• In data communications, data elements are to be send; A data element is the smallest entity that can represent a piece of information: this is the bit
• In digital data communications, a signal element carries data elements; A signal element is the shortest unit (timewise) of a digital signal
• In other words, data elements are what sender needs to send; signal elements are what sender can send; therefore, data elements are being carried; signal elements are the carriers

Depletion in the concentration of ozone over a restricted area as spring time decline over Antarctica is called ozone hole. An ozone hole was discovered over Antarctica by Farman et al, 1985.

• For linear applications of op-amp, the op-amp should not be driven into saturation
• Negative feedback reduces the gain of the op-amp and prevents it from going into saturation
• Op-amp goes into saturation when operated in positive or no feedback

 d) Switch

A switch operates at the data link layer, while a repeater functions at the physical layer. Therefore, only option b (Switch) is the correct answer according to standard references.

An operating system is a system software that acts as an interface between the user and the hardware resources. It provides a variety of services to the computer.

It performs all the basic tasks like file management, memory management, process management, handling input and output, and controlling peripheral devices such as disk drives and printers.

Some popular Operating Systems include Linux and Windows.

Windows Operating System

Every computer needs an operating system for operating a computer. There are few around and Microsoft Windows is just one of them. 
Some of the functions the Windows operating system allows to do are: 

• Access applications (programs) on the computer (word processing, games, spreadsheets, calculators and so on)
• Load any new programs on to the computer
• Manage hardware such as printers, scanners, mike, digital cameras
• Manage how files are stored on a computer (File Management, covered later in this module)
• Change computer settings such as colour schemes, screensavers, and the resolution of the monitor

There are several versions of Microsoft Windows in existence like Windows XP, Windows Vista, Windows 7 and Windows. 

• The relational model represents the database as a collection of relations; A relation is nothing but a table of values
• Simplicity: A relational data model is simpler than the hierarchical and network model
• Data Definition Language (DDL) statements are compiled, resulting in a set of tables stored in a special file called a data dictionary or data directory, therefore, it is both simple and compiled

Mohiniyattam and Kathakali dance are two classical dance forms associated with Kerala.

A trunk is a communications line or link designed to carry multiple signals simultaneously to provide network access between two points.

Trunks connect switching centers in a communications system.

The signals can convey any type of communications data.

Concept:

Current through a branch/resistor is zero when both its terminals are at the same potential.

Application:

Potential at B = 20 V

Since, no current flows through branch AB, all the current I flows through the parallel branch of 2 Ω.

V_A = I(2)

Since V_A = V_B

2I = 20 V

I = 10 A

Concept:

• Static variables are initialized only once.
• The compiler persists with the variable till the end of the program.
• Static variables can be defined inside or outside the function.
• They are local to the block.
• The default value of static variables is zero.
• The static variables are alive till the execution of the program

Example:

int main()

{

static int a;

printf(“%d”, a);

}

The output of the above program is:

0

Secondary pollutants: Primary pollutants when reacting with each other or from basic components of air, forms a new pollutant called secondary pollutants.

Different types of secondary pollutants include:

1. Ozone (O3)

2. Sulfuric acid and nitric acid (a component of acid rain)

3. Particulate matter

4. Nitrogen dioxide (NO2)

5. Peroxyacyl nitrates (PAN)

6. Photochemical smog

Primary pollutants:  Pollutants that are emitted directly from either natural events or from human activities are called primary pollutants.

The natural events are dust storms; volcano etc and human activities can be emission from vehicles, industrial wastes.

About 90% of global air pollution is constituted by five primary pollutants. These are

1. Carbon oxides (CO and CO2)

2. Nitrogen oxides

3. Sulphur oxides

4. Hydrocarbons

5. Particulate matter

6. Volatile Organic Compound

7. Suspended Particulate Matter (SPM)

8. Radioactive compound

9. Halogen compound