BEL Trainee Engineer Electronics Mock Test - 6 - Electronics and Communication Engineering (ECE) MCQ

Hexadecimal representation system

A is represented by 1010 and 4 is represented by 0100.

4A = 01001010

The left most number is 0, so 4A can be represented as 1001010

The correct answer is option 3.

Concept:

The given circuit is,

The resultant expression is,

Y= (A+B). C.D.E   here (.) is and operation and (+) is or operation

Y=(A+B).CDE

This is also written as,

Y=C(A+B)DE

Hence the correct answer is C(A+B)DE.

The correct answer is option 3.

Concept:

Statement 1: The Uniform Resource Identifier is a set of rules which is used to retrieve linked web pages across the web.

False, The HyperText Transfer Protocol is a set of rules which is used to retrieve linked web pages across the web. The more secure and advanced version is HTTPS. 

HTTP is a protocol for fetching resources such as HTML documents. It is the foundation of any data exchange on the Web and it is a client-server protocol, which means requests are initiated by the recipient, usually the Web browser.

Statement 2: HyperText Transfer Protocol is a unique address or path for each resource located on the web.

False,  URI (Uniform Resource Identifier) or URL (Uniform Resource Locator) is a unique address or path for each resource located on the web.

A Uniform Resource Identifier (URI) is a character sequence that identifies a logical (abstract) or physical resource usually, but not always, connected to the internet.

Hence the correct answer is Both statement 1 and statement 2.

Sampled data system:

When the signal or information at any or some points in a system is in the form of discrete pulses, then the system is called discrete data system or sampled data system.

The following methods suitable for the stability analysis of sampled data control systems.

• Jury’s stability test
• Root locus technique
• Bilinear transformation

Merits:

• Systems are highly accurate, fast and flexible
• Use of time sharing concept of digital computer results in economical cost and space.
• Digital transducers used in the system have better resolution.
• The digital components are less affected by noise, non-linearities and transmission errors of noisy channel.

Demerits:

• Conversion of analog signals to discrete-time signals and reconstruction introduce noise and errors in the signal.
• Additional filters have to be introduced in the system if the components of the system does not have adequate filtering characteristics.

Since at t = 0, the switch is closed.

So at t > 0, the circuit will be.

Redrawing above circuit in s-domain – 

          

i(t) = 10 u(t) Amp

NOTE:

Since the switch is closed t ≥ 0

So 10 V will work only after t ≥ 0 that’s why we take voltage source as 10 u(t). In Laplace or s-domain  

Cleavage plane:

• When a crystal is break or fracture easily along a definite plane then this plane is called cleavage plane.
• It is used to identity mineral and its quality.
• It forms generally in a lower energy crystal structure.
• In silicon, most preferred cleavage plane is < 111 >

Silicon have two cleavage plane < 111 > and < 110 >

Intersymbol Interference (ISI):

• It is a form of distortion, where one symbol interferes with subsequent symbols.
• ISI causes due to the spreading of pulse width beyond its limit.
• Due to ISI decision device shows error at the receiver.
• A major cause to arise ISI is multipath propagation and transmission of the signal through a band-limited channel.
• ISI can be analyzed with the help of an eye diagram:

• Eye diagram can be observed in an oscilloscope
• The width of the eye diagram represents wave can be sampled without ISI in an interval.
• The height of the eye-diagram represents wave is sampled at a specific time that defines the margin over the noise.

Finite Impulse Response (FIR) filter

• In signal processing, a finite impulse response (FIR) filter is a filter whose impulse response is of finite duration because it settles to zero in finite time.
• FIR filters can be discrete-time or continuous-time, and digital or analog.
• The impulse response of an Nth-order discrete-time FIR filter has exactly N+1 samples.
• For a linear-phase filter, group delay and phase delay are of the same value. So linear-phase filters are also called Constant Time Delay Filters.
• An FIR filter is a linear phase if its coefficients are symmetrical or anti-symmetrical around the center coefficient.

Waveguides are used to direct and propagate Electromagnetic waves from one point to another. They are generally used to transmit high frequency waves such as Microwaves, Radio waves, Infrared waves etc.

The signals with high frequencies are allowed to propagate through the waveguide whereas the signals below the frequency will face a high reflection.

Waveguides are classified into two types:

1. Metal waveguides: Metal waveguides consists of enclosed conducting metal pipe and the wave guiding principle works on the total internal reflection.

2. Dielectric waveguides: These waveguides consists of dielectrics and the reflection from dielectric interfaces helps in the propagation of electromagnetic waves along the waveguide.

Metal waveguides are classified into two types:

1. Rectangular waveguides  2. Circular waveguides

A circular waveguide is a hollow metallic tube with circular cross section for propagating the electromagnetic waves by continuous reflections from the surfaces or walls of the guide.

A waveguide with a circular cross section is called as circular waveguide. It supports both Transverse electric (TE) and Transverse magnetic (TM) modes..

TM₀₁ mode is preferred to TE₀₁ as it requires a smaller diameter for the same cut-off wavelength.

The waveguides of circular cross section are used to transmit EM waves from one point to another.

The root values for the TM modes are:

  01 = 2.405 for TM01

  02 = 5.53 for TM02

  11 = 3.85 for TM11

  12 = 7.02 for TM12 

The dominant mode for a circular waveguide is defined as the lowest order mode having the lowest root value. 

The circular waveguides are perfectly symmetrical around the axis. Because of it's symmetrical nature, the dominant mode for TM waves in a circular waveguide is TM₀₁. The dominant mode TM₀₁ has the lowest root value of 2.405.

conclusion: option 2 is correct

In electronic switching systems, the control functions are performed by a computer or a processor. Hence these systems are called Stored Program Control (SPC) systems.

New facilities can be added to a SPC system by changing the control program.

Classification of switching systems is shown below:

Concept:

• An optical time-domain reflectometer (OTDR) is an optoelectronic instrument used to characterize an optical fiber.
• The Optical Time Domain Reflectometer (OTDR) is useful for testing the integrity of fiber optic cables.
• OTDR is used to verify splice loss, find faults, and measure the length of optical communication.
• The instrument emits short laser pulses, e.g. with pulse durations of some tens of nanoseconds and peak power of a few hundred milliwatts, as can be obtained with a single-mode laser diode.
• The pulses are injected through a launch cable into the tested optical fiber.
• Any reflected light is extracted with a directional fiber coupler and sent to a fast and sensitive photodetector.
• The photodetector allows for the time-resolved measurement of the reflected optical power and thus of the return loss.
• One can find the propagation losses and also find whether the loss coefficient is constant along with the fire or changes locally. 

The correct answer is 1024 megabytes.

Key Points

• 1 gigabyte = 2³⁰ bytes = 2¹⁰ × 2²⁰ bytes
• Since 1 megabyte =  220 bytes
• 1 gigabyte =  2¹⁰ × megabytes
• 1 gigabyte = 1024 megabytes
• Therefore option 3 is correct.

Important Points

• The smallest unit of memory is called a bit.
• Bit stands for binary digit.
• The memory of a computer is measured in Bytes
• The storage capacity of a hard disk is measured in Megabytes, Gigabytes, and Terabytes.

Additional Information

Memory Size is as follows:

Non-Maskable interrupts.

An interrupt that cannot be ignored or disabled by the instructions of the CPU is called as Non-Maskable interrupts

It requires the processor to process them immediately.

Example: Trap of 8085

Maskable interrupt:

The hardware interrupts which can be delayed when a much high priority interrupt has occurred at the same time is called a maskable interrupt.

CONCEPT:

• Potentiometer: The instrument designs for measuring the unknown voltage by comparing it with the known voltage, such type of instrument is known as the potentiometer.
• In other words, the potentiometer is the three-terminal device used for measuring the potential differences by manually varying the resistance. The known voltage is drawn by the cell or any other supply sources.

CHARACTERISTICS OF POTENTIOMETER

• The potentiometer is very accurate because it works on the comparing method rather than the deflection pointer method for determining the unknown voltages.
• It measures the null or balance point which does not require power for the measurement.
• The working of the potentiometer is free from the source resistance because no current flows through the potentiometer when it is balanced.

WORKING OF POTENTIOMETER

• The working principle of the potentiometer is explained through the circuit shown below.
• consider S is the switch used for connecting or disconnecting the galvanometer from the potentiometer. 
• The battery through the rheostat and slide wire supply the working current.
• The working current may vary by changing the setting of the rheostat.

• The method of findings the unknown voltage depends on the sliding position of the contact at which the galvanometer shows the zero deflection. 
• The Zero or null deflection of galvanometer shows that the potential of the unknown source E and the voltage drops E1 across the sliding wires are equal. Thus the potential of the unknown voltage drops across the ac portion of the sliding wire.
• The slide wire has the uniform cross-section and resistance across the entire length. As the resistance of the sliding wire is known, then it is easily controlled by adjusting the working current. 
• The process of equalising the working voltage drop is known as the standardization.

Explanation:

A galvanometer can be converted into a voltmeter by connecting a large resistance in series with it.

The correct phrasal verb with verb ‘stem’ is ‘stem from’.

Stem from: to be caused by (something or someone).

Ex: Most of her health problems stem from an accident she had when she was five.

Hence, option A is correct.

Note :- Rule to make active voice of Simple Past Tense
We can say that ,
The above given sentence is given in Passive Voice :-
Use structure “subject + auxiliary + past participle + by + object”
That watch was stolen by him.
Hence , required sentence is option A .

The author makes this clear in the fourth sentence of the passage that a man of knowledge possesses immense influence in society

The author considers that a man of knowledge is reformative in his approach. He can tun the sleeping people into a thundering force.

Definition of an Extranet:
An extranet is a private computer network that allows authorized users from different organizations to access shared information, collaborate, and communicate securely over the internet.
Explanation:
The correct answer is B: The intranets of two co-operating organizations interconnected via a secure leased line.
- An extranet is an extension of an organization's intranet, which is a private network accessible only to employees or members of the organization.
- It is used to provide controlled access to external parties such as suppliers, partners, or customers.
- The extranet allows these external parties to connect to the organization's intranet and access specific resources or information based on their authorization level.
- The connection between the two intranets is established via a secure leased line, ensuring the confidentiality and integrity of the data transmitted.
- The extranet provides a secure and collaborative environment for organizations to share data, documents, and applications with their trusted partners, suppliers, or customers.
- It enables efficient communication, streamlined business processes, and improved collaboration between organizations.
Key Points:
- An extranet is a private computer network.
- It allows authorized users from different organizations to access shared information.
- It enables collaboration and communication securely over the internet.
- It is an extension of an organization's intranet.
- It connects the intranets of two cooperating organizations.
- The connection is established via a secure leased line.

The correct answer is B: Select the image.
To delete an object, you must first select the object before performing any further actions. Here are the steps to delete an object:
1. Select the image:
- Click on the image to select it.
- This step is crucial as it indicates which object you want to delete.
2. Delete the image:
- Once the image is selected, you can proceed with deleting it.
- Press the Delete key on your keyboard or right-click on the image and choose the Delete option.
3. Confirm the deletion:
- In some cases, a confirmation dialog box may appear to confirm the deletion.
- Read the message carefully and click on the appropriate option to confirm the deletion.
4. Verify the deletion:
- After confirming the deletion, ensure that the image has been successfully removed from the location where it was placed.
Remember that these steps may vary depending on the software or application you are using to delete the object. However, the general principle of selecting the object before deleting it remains the same.

The formula `="$55.00"+5` in a spreadsheet cell will concatenate the string `"$55.00"` with the number `5`, treating the number as a string. This results in the output `"$55.00+5"`, which is not a numerical calculation but a text string.

The correct answer is:

b) “$55.00″+5

Reasons for Process Suspension:
Swapping parent process:
- When the operating system needs to free up memory resources, it may decide to swap out a parent process. This means that the process is moved from main memory to secondary storage (such as a hard disk) temporarily.
- Swapping allows the operating system to prioritize active processes and allocate resources efficiently.
Inter request:
- Process suspension can occur when a process needs to wait for an external event or resource before it can continue executing.
- For example, if a process is waiting for user input or waiting for a file to be read from the disk, it may be temporarily suspended until the requested input or data becomes available.
Timing:
- Timing can also be a reason for process suspension. This occurs when a process is scheduled to be suspended for a specific period of time, allowing other processes to execute during that time frame.
- Timing-based suspensions are often used in multitasking operating systems to ensure fair allocation of resources among different processes.
All of the above:
- The correct answer to the question is "d. All of the above" because all of the mentioned reasons (swapping parent process, inter request, and timing) can lead to process suspension.
In summary, process suspension can occur due to various reasons such as the need for memory management (swapping parent process), waiting for external events or resources (inter request), and timing-based scheduling. All of these reasons contribute to the efficient allocation of resources and fair execution of processes in an operating system.

To determine which function will return a value of 8, let's analyze each function separately:
A: ROUNDUP(8.4999, 0)
- The ROUNDUP function rounds a number up to a specified number of decimal places.
- In this case, the number 8.4999 is already an integer, so rounding it up will not change its value.
- Therefore, the result of ROUNDUP(8.4999, 0) will be 8.
B: ROUNDDOWN(8.4999, 0)
- The ROUNDDOWN function rounds a number down to a specified number of decimal places.
- In this case, the number 8.4999 is already an integer, so rounding it down will not change its value.
- Therefore, the result of ROUNDDOWN(8.4999, 0) will be 8.
C: ROUND(8.4999, 0)
- The ROUND function rounds a number to a specified number of decimal places.
- In this case, the number 8.4999 is already an integer, so rounding it to 0 decimal places will not change its value.
- Therefore, the result of ROUND(8.4999, 0) will be 8.
D: Only B and C
- Based on the analysis above, both ROUNDDOWN(8.4999, 0) and ROUND(8.4999, 0) will return a value of 8.
- Therefore, the correct answer is D, which states that only options B and C will return a value of 8.
In summary, the functions ROUNDDOWN(8.4999, 0) and ROUND(8.4999, 0) will both return a value of 8.

The correct syntax in Excel is option A: `=IF(LogicalTest, TrueResult, FalseResult)`. Here's a detailed explanation:
IF Function in Excel:
The IF function in Excel is used to perform logical tests and return different values based on the result of the test. It follows the syntax: `=IF(LogicalTest, TrueResult, FalseResult)`, where:
- `LogicalTest` is the condition that is being evaluated.
- `TrueResult` is the value or expression that is returned if the logical test is true.
- `FalseResult` is the value or expression that is returned if the logical test is false.
Explanation of the Given Syntax:
The correct syntax in Excel is option A: `=IF(LogicalTest, TrueResult, FalseResult)`. Let's break it down:
- `IF`: This is the function name that indicates we are using the IF function in Excel.
- `LogicalTest`: This is the condition that is being evaluated. It can be a comparison, a formula, or any expression that returns a logical value (TRUE or FALSE).
- `TrueResult`: This is the value or expression that is returned if the logical test is true. It can be a number, text, formula, or reference to a cell or range.
- `FalseResult`: This is the value or expression that is returned if the logical test is false. It can also be a number, text, formula, or reference to a cell or range.
Incorrect Syntax:
Let's also explain why the other options are incorrect:
- Option B: `=IF(LogicalTest, (TrueResult, FalseResult)`: This syntax is incorrect because the TrueResult and FalseResult are enclosed in parentheses without separating them using a comma.
- Option C: `=IF(LogicalTest, TrueResult) (LogicalTest, FalseResult)`: This syntax is incorrect because it separates the TrueResult and FalseResult into separate IF functions without using the comma to separate the arguments within the IF function.
- Option D: `=IF(LogicalTest,True Result), IF (LogicalTest,   FalseResult)`: This syntax is incorrect because it separates the TrueResult and FalseResult into two separate IF functions, but there is an unnecessary comma in True Result and an unnecessary space before FalseResult.
Therefore, the correct syntax in Excel is option A: `=IF(LogicalTest, TrueResult, FalseResult)`.

To remove unwanted actions from a recorded macro without recording the whole macro again, you can follow these steps:
Step 1: Open the Visual Basic Editor
- Press Alt + F11 to open the Visual Basic Editor.
Step 2: Locate and Select the Macro
- In the Visual Basic Editor, locate the macro that contains the unwanted action.
- Select the macro by clicking on its name in the Project Explorer window.
Step 3: Edit the Macro Code
- Once the macro is selected, the code corresponding to the macro will be displayed in the Code window.
- Scroll through the code to find the unwanted action that you want to remove.
Step 4: Remove the Unwanted Action
- Place your cursor on the line of code that represents the unwanted action.
- Press the Delete key to remove the line of code.
- Repeat this process for any other unwanted actions that you want to remove.
Step 5: Save and Close the Visual Basic Editor
- After removing the unwanted actions, save the changes by clicking on the Save button or pressing Ctrl + S.
- Close the Visual Basic Editor by clicking on the Close button or pressing Alt + Q.
The unwanted actions have now been removed from the recorded macro without having to re-record the entire macro.

The correct answer is F12.

Key Points

• Save the current document: Press Ctrl + S to save the current document immediately.
• Open the Save As window: Press F12 to open the Save As dialog box to save the document with a specific filename or in a new folder. 
• F8 - Toggles whether to extend a selection with the arrow keys.
• F9 - Updates all the field codes in the current selection.
• F10 - Toggles the display of the ribbon shortcut keys otherwise known as Access Keys.

Additional Information

Important Shortcut keys used in MS Word:

• Cut the selected content to the Clipboard - Ctrl+X.
• Copy the selected content to the Clipboard - Ctrl+C.
• Paste the contents of the Clipboard -Ctrl+V.
• Increase the font size by 1 point.- Ctrl+].
• Center the text - Ctrl+E.
• Align the text to the left - Ctrl+L .

U is the mother of P and R is the brother of P. So, U is mother of R.

The given group consists of different Indian ethnicities or cultural groups. The options provided need to identify another group that fits this classification.

• Aryan refers to a historical group, but it is less relevant in the current context.
• Dravidan is a term used for a major cultural group in South India, making it a possible candidate.
• Marathi represents a linguistic and cultural group from Maharashtra, which aligns with the others.
• Barbarian does not fit as it is not an ethnicity or cultural group within India.

Thus, the most fitting choice that belongs to the same category is Marathi.

The sequence is a combination of two series:

I. 19, 38, 114, (____)
II. 2, 3, 4

Considering Series I:
1st term = 19
2nd term = 19*2 = 38
3rd term = 38*3 = 114
Thus, the missing number is 4th term = 114 * 4 = 456

Given:

x + y + 1 = 0

Concept Used:

(a + b )³ = a³ + b³ + 3ab (a + b)

Calculations:

x + y + 1 = 0

⇒ x + y = -1

Cubing on both sides we get

(x + y)³ = ( -1 )³

⇒ x³ + y³ + 3xy( x + y ) = -1

⇒ x³ + y³ + 3xy ( -1) = -1

∵ x + y = -1

⇒ x³ + y³ - 3xy = -1

∴ required value = -1