RRB JE ECE (CBT II) Mock Test- 6 - Electronics and Communication Engineering (ECE) MCQ

The various stages of op-amp are shown in the figure:
The last stage/output stage is the Push Pull amplifier

When no voltage is applied to these deflection plates, the electron beam produces a spot of light at the center as shown by point O in fig below on the screen.

The intensity of the light spot on the screen can be controlled by changing the negative potential on the control grid.

FDM transmitter:

• The available bandwidth of a single physical medium is divided into a number of smaller, independent frequency channels
• Using modulation, independent message signals are translated into different frequency bands

FDM Receiver:

• At the receiving end, the signal is applied to a bank of band-pass filters, which separates individual frequency channels
• The bandpass filter outputs are then demodulated and distributed to different output channels

Power factor: It is the ratio between true power and apparent power

Power factor = kW/kVA

Form factor: It is the ratio of the RMS (root mean square) value to the average value

Load factor: It is defined as the ratio of the average load over a given period to the maximum demand (peak load) occurring in that period.

Diversity factor: It is the ratio of sum of individual maximum demand to maximum demand on power station

The generations of computers are characterized by a major technological development that fundamentally changed the way computers operate, resulting in smaller, cheaper, more powerful and more efficient and reliable devices.

The various generations of computers are listed below:

• Virtual ground concept is valid for only Negative feedback systems
• Negative feedback systems decrease the differential input voltage between and non-inverting terminals

When difference becomes zero, the voltage at two terminals become equal, which is a virtual ground concept

Azhar takes 45 days less to finish a job and is 4 times more efficient than Balraj.
Therefore, let Balraj takes x days then Azhar takes x – 45 days.
Now, as per the question if Balraj takes 4D days then Azhar should take 4D days to
complete the job.
X/X - 45 = 4D/D
⇒ x =4x - 180
⇒ x = 60 days
Thus, Balraj takes 60days and Azhar takes (60 – 45) = 15 days to finish the job.
Working together, they need

percentage regulation =  X 100%
5/100 = 
5/100 . (24) = (V_NL - 24)
V_NL = 25.2

At resonance
X_c = X_L

In an N-type semiconductor the doping done is of pentavalent atoms.
As the doping density increases the fermi level moves towards the conduction band.
If N_D is the doping density, then the upward shift in the fermi level is given by
shift = kTln (N_D/n_i)
From the expression
As N_D increases N_D/n_i increases and the shift increases.

Ground Waves:

Middle frequency contains frequencies in range 300 kHz to 3 MHz.

These waves travel mainly by reflection from the ground surface and are called Ground waves.

MF is mostly used for AM radio broadcasting, navigational radio beacons, maritime ship-to-shore communication, and transoceanic air traffic control.

Sky Waves:

Skywave refers to the propagation of radio waves reflected or refracted back toward Earth from the ionosphere, an electrically charged layer of the upper atmosphere.

Space Waves:

The high-frequency electromagnetic wave is not reflected back by the ionosphere, so to use high-frequency electromagnetic wave in communication we used space wave propagation.

• Space waves are used in two types of communication −
• Line-of-sight (LOS) propagation.
• Satellite communication

Vermicompost is the product of the composting process using various species of worms, usually red wigglers, white worms, and other earthworms, to create a mixture of decomposing vegetable or food waste, bedding materials, and vermicast. This process of increasing fertility of soil by earthworms is known as vermicomposting.

Important Points:

Eutrophication: It is an enrichment of water by nutrient salts that causes structural changes to the ecosystem.

Compounds that contain nitrogen and phosphorus (fertilizers) drives the eutrophication. These nutrients are generally not toxic.

The Battle of Waterloo was fought between the French army commanded by Napoleon Bonaparte and the British army led by the Duke of Wellington in 1815.

The Battle of Waterloo is considered one of the most dreadful battles in history. In this war, the Duke of Wellington defeated Napoleon Bonaparte.

Napoleon surrendered in front of British forces after a few months. He was sent to St. Helena where he died in 1921.

Given that, bandwidth (B.W.) = 10 Hz
Raise time is, t _r = 0.35/B.W. = 0.35/10 = 0.035 = 35 ms

Using,
1/f = 1/v - 1/u
Where,
f = focal length = -20 cm
v = Image distance = v
u = Object distance = -40 cm
1/-20 = 1/v - (1/-40)
v = -13.33 cm

• River Sutlej originates outside India, at Mount Kailash, Tibet.
• It enters India through Shipki la Pass.
• Yamuna River originates at Yamunotri Glacier, Uttarakhand.
• Ganga River originates at Gaumukh, Gangotri Glacier, Uttarakhand.
• Luni is the only river that flows in Rajasthan.

Ransomware is a type of malicious software that threatens to publish the victim's data or perpetually block access to it unless a ransom is paid

• In May 2017, WannaCry ransomware targeted computers running the Microsoft Windows operating system by encrypting data and demanding ransom payments in the Bitcoin cryptocurrency
• Around 37 incidents of ransomware attacks were reported to the Indian Computer Emergency Response Team (CERT-In), according to Minister of State for Electronics and IT

Adware is any software application in which advertising banners are displayed while a program is running

Spyware is mostly used for the purposes of tracking and storing internet user movements on the web and provides pop-up ads to the internet user

Trojan horse is a program that appears harmless but in fact malicious which misleads user of its true intent

In order to convert a Galvanometer into voltmeter, a very high resistance known as "series resistance" is connected in series with the galvanometer.

Consider an example:

{

int a[10]; \ the system reserves memory for 10 elements of array

a[11] = 12; \ enter the value into the 11 the element of array which was not defined

printf(“%d”, a[11]);

}

Now if the 11^th element tries to overwrite the space which is occupied by some other important data, the program may crash.

Click on the webpage and use the appropriate keyboard shortcut:

• For Chrome OS and Windows, use Ctrl + S.
• For Mac OS X and macOS Sierra, use Command + S.

Clicking the Print button on the toolbar instantly prints the web page.

• To work the Print dialogue box, choose Print from the Print button’s menu or press Ctrl + p
• Ctrl + F4 and Ctrl + w both closes current window.

Alt + F6 toggles windows. Alt + F8 toggles find result windows.

Concept:

• The propagation constant of a wave is complex quantity and is given by γ.
• The propagation constant of a sinusoidal electromagnetic wave is a measure of the change undergone by the amplitude and phase of the wave as it propagates in a given direction.
• The quantity being measured can be the voltage, the current in a circuit, or a field vector such as electric field strength or flux density

Application:

Mathematically propagation constant γ is written by

γ = α + j β

γ = propagation constant

α = real part = Attenuation constant

β = Imaginary part = Phase constant

Attenuation constant:

• Attenuation constant gives attenuation of an electromagnetic wave propagating through a medium per unit distance from the source.
• It is the real part of the propagation constant and is measured in nepers per metre.

Phase Constant:

• The phase constant is the imaginary component of the propagation constant for a plane wave.
• It represents the change in phase per unit length along the path travelled by the wave at any instant.
• Phase constant is measured in radians per unit length

The various instructions and flags they affect is given by:

For INX and DCX instructions no flags affected

Input is any data or information is sent to computer for processing it into meaningful information. Input devices feed data to the computer system for processing. Eg.Keyboard.

Primary Memory:

Primary memory is the main memory of the computer system.

Accessing data from primary memory is faster because it is an internal memory of the computer.

The primary memory is most volatile which means data in primary memory does not exist if it is not saved when a power failure occurs.

The primary memory is a semiconductor memory.

It is costlier compared with secondary memory.

The capacity of primary memory is very much limited and is always smaller compares to secondary memory.

E.g. RAM, ROM        

Secondary Memory:

All secondary storage devices which are capable of storing high volume data is referred to secondary memory.

It's slower than primary memory.

It can save a substantial amount of data, in the range of gigabytes to terabytes.

This memory is also called backup storage or mass storage media.

The first two MVI instruction stores the data in H and L registers respectively

H ← 40

L ← 20

The last instruction MVI M, 10 H will store the data 10 in the memory location pointed by HL pair

[4020] ← 10

Thus, the content of HL pair is unaffected by last MVI instruction

Na, Ca and Mg are reactive metals and quickly react with water.

At room temperature, the reaction of Fe is very slow but red-hot iron reacts with steam to form Fe₃O₄ with hydrogen gas.

3Fe + 4H₂O → Fe₃O₄ + 4 H₂

A transmission line of finite length that is terminated at one end with an impedance equal to the characteristic impedance appears to the source like an infinitely long transmission line and produces no reflections.

The behaviour of transmission line due to variation in length is tabulated below:

Concept:

According to Kirchhoff’s current law (KCL), the algebraic sum of the electric currents meeting at a common point is zero. I.e. the sum of currents entering a node is equal to the sum of currents leaving the node. It is based on the conservation of charge.

Calculation:

By applying KCL,

i1 + i5 = i2 + i3 + i4

The File Transfer Protocol (FTP) is a standard network protocol used to transfer data from one medium to another over a TCP-based network, such as the Internet. It is usually built on a client-server format and uses control and data connections between the client and the server. It is one of most widely used systems to transfer data from one computer to another.