Short Questions (60*1=60 Marks)

Answer:

4) $N_{dB} = 10 \log_{10}\left(\frac{V_2}{V_1}\right) + 10 \log_{10}\left(\frac{Z_2}{Z_1}\right)$

Explanation:

The decibel power gain is derived from the power ratio:
$P = \frac{V^2}{Z}$

Substituting this into the decibel formula for power gain:
$N_{dB} = 10 \log_{10}\left(\frac{P_2}{P_1}\right)$
$N_{dB} = 10 \log_{10}\left(\frac{V_2^2 / Z_2}{V_1^2 / Z_1}\right)$

Simplifying:
$N_{dB} = 10 \log_{10}\left(\frac{V_2^2}{V_1^2}\right) + 10 \log_{10}\left(\frac{Z_1}{Z_2}\right)$

This is rewritten using the voltage ratio:
$N_{dB} = 10 \log_{10}\left(\frac{V_2}{V_1}\right) + 10 \log_{10}\left(\frac{Z_2}{Z_1}\right)$

Answer:

3) 50%

Explanation:

According to the Maximum Power Transfer Theorem:

• Maximum power is transferred when the load resistance $( R_L )$ equals the source resistance $( R_S )$.
• At this point, 50% of the total power is dissipated in the load, and the remaining 50% is lost in the source resistance.

Answer:

3) 1.0

Explanation:

The power factor is defined as the ratio:
$\text{Power Factor} = \frac{\text{Real Power}}{\text{Apparent Power}} = \frac{R}{Z}$

• The maximum value of the power factor is 1.0, which occurs when the circuit is purely resistive (( Z = R ), no reactive components like inductance or capacitance).

Answer:

2) 10 nm

Explanation:

• EEPROM (Electrically Erasable Programmable Read-Only Memory) uses a floating gate to store charges.
• The gap between the drain and floating gate is typically designed to be around 10 nm to ensure reliable charge retention and efficient erase/program cycles.

Answer:

4) Signal of band 100MHz-105MHz can be generated

Explanation:

According to the Heisenberg Uncertainty Principle:

• The uncertainty in time $(( \Delta t ))$ and frequency $(( \Delta f ))$ is related as:
  $\Delta t \cdot \Delta f \geq \frac{1}{2\pi}$
• This implies that precise signals cannot be generated at a single frequency, but rather within a band of frequencies. Hence, a signal band of 100MHz-105MHz is feasible.

Answer:

3) Class C amplifier

Explanation:

• UHF (Ultra-High Frequency) signals operate in the range of 300 MHz to 3 GHz.
• Class C amplifiers are specifically designed for high-frequency applications like UHF due to their high efficiency and narrowband operation.
• These amplifiers are commonly used in RF transmitters.

Answer:

1) 11100100

Explanation:

• To calculate the two’s complement of a binary number:
  1. Invert all the bits of the number: ( 00011011 \to 11100100 ).
  2. Add 1 to the result: ( 11100100 + 1 = 11100101 ).
• The result is ( 11100100 ), representing the negative equivalent in two’s complement notation.

Answer:

1) Logic gate

Explanation:

• A combinational circuit is built using logic gates such as AND, OR, NOT, etc.
• These gates combine multiple inputs to produce specific outputs based on logical operations.
• Flip-flops and memory are elements of sequential circuits, not combinational circuits.

Answer:

2) Clock driven

Explanation:

• Synchronous circuits operate based on a clock signal.
• State transitions occur at specific clock edges (rising or falling), making them “clock-driven.”
• This ensures predictable timing and synchronization in the circuit.

Answer:

3) Number of bits processed per instruction

Explanation:

• The bandwidth of a microprocessor refers to the number of bits it can process in a single instruction.
• For instance, an 8-bit microprocessor processes 8 bits per instruction.
• This is determined by the architecture and design of the processor.

Answer:

2) 8 bit

Explanation:

• The Programmable Peripheral Interface (PPI) 8255 has an 8-bit internal data bus.
• This allows it to interface directly with 8-bit microprocessors for data transfer.
• It is commonly used in microprocessor-based systems for parallel data communication.

Answer:

2) With pause of current instructions

Explanation:

• When an interrupt occurs, the current instruction execution is paused, and the processor jumps to execute the ISR.
• After completing the ISR, the processor resumes execution of the interrupted instruction.

Answer:

1) To print output to the console

Explanation:

• The printf() function is used to display output on the console.
• It can format text, variables, and special characters to provide user-readable output.
• Example: printf("Hello, World!"); prints “Hello, World!” to the console.

Answer:

2) To move the file pointer to the beginning of the file

Explanation:

• The rewind() function resets the file pointer to the start of a file.
• This is useful when you need to re-read the file from the beginning without closing and reopening it.
• Example: rewind(filePointer); resets the file pointer of filePointer.

Answer:

2) Private

Explanation:

• Members declared as private are only accessible within the class itself.
• They are not accessible from derived classes or outside the class.
• This ensures encapsulation and protects sensitive data or implementation details.

Answer:

3) To initialize data members of a class

Explanation:

• A constructor is a special member function in C++ used to initialize objects of a class.
• It is called automatically when an object is created.
• Its primary purpose is to set initial values for the data members of an object.

Answer:

4) They can only be declared in the base class

Explanation:

• A pure virtual function is a function declared in the base class with no definition and is meant to be overridden by derived classes.
• It is used to create abstract classes and enforce that derived classes implement the function.
• Example: virtual void function() = 0;

Answer:

1) To catch exceptions that are thrown by the program

Explanation:

• The try block is used to define a section of code in which exceptions may occur.
• If an exception is thrown within the try block, it is caught by a corresponding catch block to handle the error.

Answer:

3) Inverted addressing mode

Explanation:

• Direct, indirect, and indexed addressing modes are valid types of addressing modes in computer architecture.
• “Inverted addressing mode” is not a standard addressing mode.

Answer:

4) The cache should store frequently used data to reduce memory access time

Explanation:

• The main goal of cache memory is to store frequently accessed data to improve processing speed.
• Storing frequently used data in the cache reduces the time spent accessing slower main memory.
• A good cache design ensures that commonly used data is readily available.

Answer:

2) Reduced complexity

Explanation:

• Multiprocessor systems generally increase complexity as they require mechanisms for synchronization, communication, and resource management.
• While multiprocessors improve reliability, throughput, and resource sharing, they also introduce design complexities that need to be handled carefully.

Answer:

1) A processor that is optimized for a specific application

Explanation:

• An ASIP is a type of processor that is specifically tailored to accelerate particular applications or tasks.
• These processors combine the advantages of custom hardware and programmable processors, making them efficient for targeted uses.
• Examples include processors optimized for signal processing, cryptography, or other domain-specific tasks.

Answer:

3) To monitor the system and detect faults

Explanation:

• A watchdog timer in an RTOS is used to detect and recover from faults by monitoring the system.
• If the system becomes unresponsive or stuck, the watchdog timer triggers a reset to restore normal operation.
• This mechanism helps ensure system reliability, especially in embedded and real-time systems.

Answer:

3) Virtual Hardware Description Language

Explanation:

• VHDL stands for VHSIC (Very High Speed Integrated Circuit) Hardware Description Language.
• It is a programming language used to describe the behavior and structure of electronic systems, primarily used for designing integrated circuits.

Answer:

3) Switch

Explanation:

• A switch operates at the data link layer of the OSI model and filters traffic based on MAC (Media Access Control) addresses.
• It is used to create a network by connecting devices within the same network segment, reducing collisions compared to hubs.

Answer:

3) Hamming code

Explanation:

• Hamming code is a technique that involves adding redundant bits (parity bits) to the original data to detect and correct errors.
• It can correct single-bit errors and detect two-bit errors.

Answer:

2) Link state

Explanation:

• OSPF uses the link-state routing algorithm.
• It maintains a map of the network topology and updates routing tables based on the state of the network links. This helps to determine the shortest path between routers.

Answer:

3) TCP

Explanation:

• TCP (Transmission Control Protocol) is a connection-oriented protocol that provides reliable data transfer by establishing a connection between sender and receiver before transmitting data.
• It guarantees data delivery and maintains the order of packets through sequence numbers and acknowledgments.

Answer:

4) SMTP

Explanation:

• SMTP (Simple Mail Transfer Protocol) is used for sending and transferring emails across networks.
• It works with other protocols like IMAP and POP3 to retrieve and manage email from mail servers.

Answer:

3) Firewall

Explanation:

• A firewall is a network security device that monitors and controls incoming and outgoing network traffic based on predefined security rules.
• It acts as a barrier between trusted internal networks and untrusted external networks, such as the internet, preventing unauthorized access.

Answer:

1) Zero

Explanation:

• In a dielectric-conductor boundary, the tangential component of the electric field is zero at the boundary.
• This is because the conductor acts as a perfect electric shield, preventing tangential electric field lines from existing at its surface.

Answer:

3) Magnetic field directly proportional to current through the conductor.

Explanation:

• Bio-Savart’s Law relates to the magnetic field generated by an electric current in a conductor.
• The magnetic field is directly proportional to the current and the geometry of the conductor.
• The cross-sectional area does not directly affect the magnetic field in Bio-Savart’s Law.
• The law does not deal with electric fields, but with magnetic fields generated by electric currents.

Answer:

3) 90°

Explanation:

• In free space, the electric and magnetic field vectors in a plane wave are always perpendicular to each other.
• Therefore, the minimum angle between them is 90°.

Answer:

2) Sphere

Explanation:

• The radiation pattern of an isotropic radiator is spherical.
• An isotropic radiator radiates equally in all directions, producing a uniform radiation pattern in three-dimensional space.

Answer:

3) Yagi-Uda antennas have high bandwidth and low gain.

Explanation:

• Yagi-Uda antennas have relatively high gain and are known for their narrow bandwidth.
• The other statements are correct:
  • Lower frequencies are typically radiated near the end of the transmission line.
  • Horn antennas are used for feeding parabolic antennas.
  • Higher frequencies are indeed radiated near the feed point of the antenna.

Answer:

1) Square of the distance

Explanation:

• In free space propagation, path loss increases with the square of the distance. This is known as the inverse square law.
• The loss is proportional to the square of the distance between the transmitter and receiver.

Answer:

3) Implementation level

Explanation:

• The implementation level refers to the stage where the model is transformed into executable code that is compatible with the system.
• The abstract level refers to a higher-level design, while the application level refers to the functional design phase.

Answer:

2) h(k) = k mod m

Explanation:

• The division method of hashing uses the hash function h(k) = k mod m, where k is the key and m is the size of the hash table.
• This method ensures that the key is mapped to an index within the bounds of the table.

Answer:

2) Normal

Explanation:

• Normalization is the process of organizing data in a database to reduce redundancy and dependency.
• By using normal forms (like 1NF, 2NF, 3NF), redundancy is minimized, ensuring efficient storage and data integrity.

Answer:

2) Logs

Explanation:

• It is advisable to store logs before applying the actual transaction to the database. This helps in tracking and recovering data in case of errors or failures during the transaction.

Answer:

1) Mutual Exclusion

Explanation:

• Mutual Exclusion is a principle where only one process can access a shared resource at a time, to prevent race conditions. The enter-critical and exit-critical functions help implement mutual exclusion.

Answer:

1) Administrator User account

Explanation:

• To perform administrative tasks, you would create an Administrator User account. This account has elevated privileges to make system-wide changes.

Answer:

3) Requirement Engineering

Explanation:

• Requirement Engineering is the process of gathering, analyzing, and documenting software requirements. It involves understanding the needs of the client and translating them into functional specifications.

Answer:

1) It is a reference model mapped onto software components

Explanation:

• Reference architecture is a blueprint that provides a standard, reusable framework for designing systems. It is typically a reference model mapped onto software components that serve as a foundation for development.

Answer:

2) private

Explanation:

• The private access specifier restricts access to class members, allowing them to be used only within the class.
• This means other classes or functions can’t access or modify these members directly.
• It’s a common practice to use private for data encapsulation and hiding implementation details.

Answer:

3) Changing the behaviour of an existing operator.

Explanation:

• Operator overloading allows redefining the functionality of existing operators (e.g., +, -, etc.) for user-defined types.
• For example, you can overload the + operator to add two objects of a custom class.
• It makes user-defined classes behave like built-in types in expressions.

Answer:

1) ifstream is used for input, while ofstream is used for output.

Explanation:

• ifstream: used to read data from files (input).
• ofstream: used to write data to files (output).
• These are stream classes in C++ for file handling and are used to interact with external files.

Answer:

1) A class that can be used to create objects of different types.

Explanation:

• A class template in C++ allows the definition of a class blueprint that works with any data type.
• This enables the creation of objects for various data types without duplicating code.
• For example, you can define a class for a generic container that works with integers, floats, or any custom data type.

Answer:

3) Free space

Explanation:

• Free space is not a medium of transmission. It refers to the environment in which transmission occurs, not a physical medium like wire, microwave, or fiber optics.
• In communication systems, free space is used to describe the propagation environment, but the medium itself must be physical (like a wire or fiber).

Answer:

2) Footprint

Explanation:

• The footprint refers to the actual radio coverage area of a cell in wireless communication systems.
• It represents the region where the radio signals can reach and be reliably received.
• It is essential for planning and optimizing network coverage.

Answer:

4) Resembles equalizer and Counter effects multipath fading

Explanation:

• The Rake Receiver is used in wireless communication to counteract the effects of multipath fading.
• It combines multiple received signals (rays) with different time delays to improve the overall signal quality.
• It acts as an equalizer by adjusting for multipath interference.

Answer:

1) 300 to 9600 bits/sec

Explanation:

• Personal communication systems, such as early mobile phones, typically have bit rates ranging from 300 to 9600 bits per second.
• This range covers the typical bit rates for older mobile communication systems like GSM and landline modems.

Answer:

2) Virtual circuit subnet

Explanation:

• ATM (Asynchronous Transfer Mode) uses a virtual circuit subnet for data transmission.
• In virtual circuit networks, a predefined path is established between the sender and receiver before data transfer.
• The ATM uses this method to ensure that data packets travel along the same path throughout the communication, which allows for more efficient data transfer.

Answer:

1) International Telecommunication Union (ITU)

Explanation:

• The ITU is the specialized agency of the United Nations responsible for setting global telecommunications standards.
• It works to ensure the efficient use of telecommunication networks and promotes international cooperation in this field.
• It also allocates global radio-frequency spectrum and satellite orbits.

Answer:

3) 297 × 420

Explanation:

• The A3 drawing sheet has standard dimensions of 297 mm × 420 mm.
• The A series of paper sizes follows a standard where each size is half of the size of the previous one when folded.
• A3 is commonly used for large-format drawings, schematics, and documents.

Answer:

3) Diminishing balance

Explanation:

• Diminishing balance method calculates depreciation at a fixed percentage of the asset’s declining book value each year.
• As the asset’s value decreases over time, the depreciation expense increases because it is calculated on the remaining book value.
• This method results in higher depreciation costs in the earlier years of the asset’s life and decreases over time.

Answer:

3) Resource smoothing

Explanation:

• Resource smoothing aims to optimize the use of available resources without extending the project duration.
• It adjusts the resource usage to ensure that resources are allocated in a balanced manner over time while keeping the project end date unchanged.
• It does not involve adding additional resources or changing the project’s timeline.

Answer:

2) Project financing

Explanation:

• Project financing involves raising funds for a specific project through various sources like equity, bonds, debentures, and preferred stock.
• It focuses on obtaining financial resources needed for project execution, ensuring that the right mix of capital sources is used.

Answer:

3) Horticultural society

Explanation:

• Horticultural society is based on the cultivation of plants for food and resources, often supporting domestic animals as well.
• People in this society primarily focus on growing crops like fruits, vegetables, and other plants that serve both human and livestock needs.

Answer:

3) Recognized

Explanation:

• According to the Nepal Engineering Council Act, 2055 (Revised, 2079), all engineering academic institutions in Nepal must be recognized by the Council.
• Recognition ensures that the institutions meet the necessary academic standards and are authorized to offer engineering education.