Past Questions — 2024

Step 1: Analyze the target word. 'Fresh' typically means new, not decayed, or recently produced (especially in the context of food or air). Step 2: Evaluate the options for an antonym (opposite meaning). - 'unfim' is not a standard English word. - 'wart' refers to a small hard growth on the skin. - 'stale' refers to food (like bread or cake) that is no longer fresh, hard, or musty; it is the direct opposite of fresh. - 'sum' refers to a total amount of money or a mathematical calculation. Step 3: Conclusion. Since 'stale' is the opposite of 'fresh', option iii is the correct answer.

The sentence describes a person's reaction to 'success in her exams,' which is a positive event. Therefore, the blank requires a word that expresses extreme happiness or joy. 1. **Ecstatic (Correct):** This means feeling or expressing overwhelming happiness or joyful excitement. It fits the context perfectly. 2. **Apoplectic (Incorrect):** This refers to being overcome with anger or being affected by a stroke. It is a negative emotion and does not fit the context of success. 3. **Caustic (Incorrect):** This describes something sarcastic in a scathing and bitter way, or chemically corrosive. It does not describe an emotional state of happiness. 4. **Copacetic (Incorrect):** This means in excellent order or satisfactory. While positive, it is typically used to describe a situation (e.g., 'Everything is copacetic') rather than a person's emotional reaction to news.

Step 1: Analyze the target word. 'Diligent' means showing care and conscientiousness in one's work or duties; it is synonymous with being hardworking and persistent. Step 2: Evaluate the options to find the opposite meaning (antonym). - Option (i) 'industrious' is a synonym of diligent, meaning hard-working. - Option (ii) 'toll' refers to a charge or a cost, which is unrelated to the target word. - Option (iii) 'greatness' refers to the quality of being great or distinguished, which is unrelated to the target word. - Option (iv) 'idle' means avoiding work, lazy, or inactive. This is the direct opposite of being diligent. Conclusion: Since 'diligent' describes a hardworking person and 'idle' describes a lazy person, 'idle' is the correct antonym.

Step-by-step reasoning: 1. Analyze the target word: 'Death' refers to the end of life or the act of dying. 2. Evaluate Option (i) 'demise': This word is a formal synonym for death, often used to describe the end of a person's life or the failure/end of an institution. 3. Evaluate Option (ii) 'yield': This means to produce or provide (e.g., a crop) or to surrender under pressure. It is not a synonym for death. 4. Evaluate Option (iii) 'sink': This means to descend below the surface of liquid or to drop to a lower level. While it can be used metaphorically, it is not a direct synonym for death. 5. Evaluate Option (iv) 'wring': This means to squeeze or twist something to force liquid out of it. It has no relation to death. Conclusion: 'Demise' is the only word among the options that shares the same meaning as 'Death'.

The idiom 'face the music' is a common English expression that means to accept the unpleasant consequences of one's own actions or mistakes. In the context of the sentence 'You should stop ignoring the problem and just face the music,' the speaker is advising the person to stop avoiding a situation and instead deal with the inevitable negative results or criticism that follow. Analysis of options: - Option (a) is the precise definition of the idiom. - Option (b) 'To confess to one’s crimes' is too narrow; while confession may be part of facing the music, the idiom applies to any unpleasant consequence, not just criminal ones. - Option (c) 'To solve ones’ problems immediately' is incorrect because 'facing the music' refers to accepting the penalty or criticism, not necessarily the act of solving the problem itself. - Option (d) 'To escape one’s situation' is the exact opposite of the idiom's meaning.

The sentence describes a lady who 'travelled alone to all corners of the globe,' which implies a high degree of courage, bravery, and a lack of fear. 1. **Intrepid (Option a):** This adjective means fearless, adventurous, and bold. It perfectly fits the context of an explorer traveling alone globally. 2. **Insipid (Option b):** This means lacking flavor, vigor, or interest (bland). It is logically incorrect in the context of a daring explorer. 3. **Elicit (Option c):** This is a verb meaning to evoke or draw out a reaction from someone. It cannot be used as an adjective to describe a person in this sentence structure. 4. **Ennobled (Option d):** This means to give someone a noble rank or to make something more noble. While a person can be ennobled, it does not describe the quality of being an adventurous explorer. Therefore, 'intrepid' is the only word that logically and grammatically completes the sentence.

Step-by-step reasoning: 1. **Analyze the target word**: 'Sympathy' refers to the feeling of pity and sorrow for someone else's misfortune; it is a state of emotional concern or compassion for others. 2. **Evaluate Option (i) 'apathy'**: Apathy is defined as a lack of interest, enthusiasm, or concern. It is the state of being indifferent or emotionally cold. Since sympathy is the presence of emotional concern and apathy is the total absence of it, 'apathy' is the direct antonym. 3. **Evaluate Option (ii) 'pain'**: Pain is a physical or emotional suffering. While sympathy is often felt *towards* someone in pain, pain itself is not the opposite of sympathy. 4. **Evaluate Option (iii) 'pity'**: Pity is a feeling of sorrow for the misfortunes of others. This is a synonym of sympathy, not an antonym. 5. **Evaluate Option (iv) 'empathy'**: Empathy is the ability to understand and share the feelings of another. This is a closely related synonym (or a deeper form of sympathy), not an antonym. Conclusion: Option (i) is the only word that represents the opposite emotional state of the target word.

The idiom 'hoist by his own petard' originates from Shakespeare's Hamlet. A 'petard' was a small bomb used to blow open gates; if the engineer (the person setting the bomb) was accidentally blown up by his own device, he was 'hoist by his own petard.' In modern usage, it means that a person's own schemes or traps intended to harm others have instead caused their own downfall. - Option (a) is correct because it accurately reflects the meaning of being undone by one's own plot. - Option (b) is too general; while the person is punished, the specific nature of the punishment (being caused by their own actions) is missing. - Option (c) refers to exposure, but the idiom implies a consequence or failure resulting from the plan, not just the discovery of it. - Option (d) is the opposite of the idiom's meaning.

In Delta Modulation (DM), the staircase approximation attempts to track the input signal. Slope Overload Distortion occurs when the rate of change (slope) of the input signal is greater than the maximum rate of change that the DM system can produce. The maximum slope of the DM staircase is given by (Δ / Ts), where Δ is the step size and Ts is the sampling period. If the input signal's slope exceeds this value, the staircase cannot 'keep up' with the signal, leading to slope overload distortion. To reduce or eliminate this distortion, we must increase the maximum slope of the staircase, which can be achieved by either increasing the step size (Δ) or increasing the sampling frequency (decreasing Ts). Therefore, increasing the step size is the correct method to reduce slope overload. Conversely, increasing the step size increases granular noise, which occurs when the signal is relatively flat.

The fundamental reason why FM provides better signal quality (specifically a higher Signal-to-Noise Ratio or SNR) than AM for the same transmitted power is the 'FM Improvement Factor' or 'Wideband Gain'. 1. **The Trade-off**: In FM, the information is encoded in the frequency deviation rather than the amplitude. By increasing the modulation index (modulation depth), the bandwidth of the signal increases. 2. **SNR Improvement**: There is a direct mathematical relationship where increasing the bandwidth (via a larger frequency deviation) allows the receiver to trade bandwidth for a significant increase in the output SNR. This is known as the wideband gain. 3. **Noise Rejection**: Because noise primarily affects the amplitude of a signal, FM receivers use 'limiters' to clip the amplitude of the incoming signal to a constant level, effectively removing most of the noise without losing the frequency-encoded information. Evaluating other options: - (a) FM is not 'immune' to noise; it is simply more resistant to it than AM. - (b) Having more sidebands is a characteristic of FM, but it is the *width* of the bandwidth and the resulting SNR gain that causes the 'better performance', not the mere count of sidebands. - (d) The capture effect is a phenomenon where the stronger of two signals is received while the weaker is suppressed; while useful, it is not the reason why a single FM station performs better than an AM station in terms of audio quality/noise.

A bolometer is a sensitive instrument used for measuring the power of incident electromagnetic radiation, including microwaves. Its operation is based on the principle that when microwave power is absorbed by a resistive element (often a thin strip of metal or a semiconductor), the temperature of that element increases. This increase in temperature causes a change in the electrical resistance of the material. By measuring this change in resistance, the amount of absorbed microwave power can be precisely determined. Why other options are incorrect: - a. Attenuator: A device used to reduce the power of a signal without significantly distorting its waveform; it does not operate by measuring resistance changes due to absorption. - c. Wave filter: A circuit designed to allow certain frequencies to pass while blocking others; it is based on frequency selectivity, not power-induced resistance changes. - d. Phase shifter: A device that changes the phase of a microwave signal; it typically operates by altering the electrical length of the transmission path or using dielectric materials, not by measuring power absorption via resistance.

VHF (Very High Frequency) waves operate in the frequency range of 30 MHz to 300 MHz. At these frequencies, the waves are too high to follow the curvature of the earth (Ground/Surface waves) and too high to be reflected by the ionosphere (Sky waves), as they penetrate through the ionosphere into space. Therefore, VHF communication relies on 'Line-of-Sight' (LOS) propagation, where the signal travels in a straight line from the transmitter to the receiver. This mode of propagation is known as Space Wave propagation. Breakdown of other options: - a. Sky waves: Typical for HF (High Frequency) waves (3-30 MHz) which reflect off the ionosphere. - b. Ground waves: Typical for VLF (Very Low Frequency) and LF (Low Frequency) waves that follow the earth's curvature. - d. Surface waves: Another term for ground waves, applicable to low-frequency signals.

To determine why satellite communication is preferred over submarine cables, we must evaluate the inherent characteristics of both media: 1. **Cost (Option a):** While launching a satellite is expensive, the cost of laying thousands of kilometers of submarine cables across oceans is also immense. However, satellites are not universally 'lesser cost' in all scenarios; they are more cost-effective for reaching remote or sparsely populated areas where cable installation is physically or economically impossible. 2. **Speed/Latency (Option b):** This is incorrect. Submarine cables use fiber optics, where signals travel at a significant fraction of the speed of light. Satellites (especially Geostationary ones) introduce a significant propagation delay (latency) because the signal must travel to space and back (approx. 35,786 km each way), making them slower than cables for real-time interaction. 3. **Multiple Access (Option c):** While satellites use multiple access techniques (FDMA, TDMA, CDMA), submarine cables also support massive multiplexing (WDM - Wavelength Division Multiplexing) that allows millions of simultaneous calls and data streams. This is not the primary reason for preferring satellites. 4. **Range of Services (Option d):** This is the correct answer. Satellites provide a unique versatility that cables cannot. They offer: - **Broadcasting:** One-to-many communication (TV, Radio) over entire continents. - **Mobility:** Communication with ships, aircraft, and remote handheld devices. - **Global Coverage:** Ability to connect any two points on Earth regardless of terrain or ocean depth. - **Rapid Deployment:** A satellite can provide coverage to a disaster zone immediately, whereas a cable takes years to lay. Therefore, the ability to offer a wide range of services (broadcasting, mobile connectivity, and global reach) makes them preferred over the fixed-point nature of submarine cables.

In microprocessor architecture, the Accumulator is a special-purpose register that serves as the primary register for all arithmetic and logic operations. When the Arithmetic Logic Unit (ALU) performs a calculation (such as addition or AND/OR operations), one of the operands is typically stored in the accumulator, and the final result of that operation is written back into the accumulator. Why other options are incorrect: - a. Stack Pointer (SP): This register stores the memory address of the last program request in a stack (LIFO structure), used primarily for function calls and interrupts. - b. Program Counter (PC): This register holds the memory address of the next instruction to be fetched and executed. - c. Instruction Pointer (IP): This is essentially another name for the Program Counter (commonly used in x86 architecture) and does not store calculation results.

Step-by-step calculation: 1. **Determine the capacity of a single memory chip**: - The chip has 12 address lines. The number of addressable locations is $2^{12} = 4096$ locations. - The chip has 4 data lines, meaning each location stores 4 bits (a nibble). - Total capacity of one chip = $4096 \times 4$ bits = $16,384$ bits. 2. **Convert the chip capacity to bytes**: - Since 8 bits = 1 byte, the capacity of one chip = $16,384 / 8 = 2048$ bytes (or 2 KB). 3. **Determine the total required memory size**: - Total required size = 32 kbyte = $32 \times 1024$ bytes = $32,768$ bytes. 4. **Calculate the number of chips required**: - Number of chips = (Total required size) / (Capacity of one chip) - Number of chips = $32,768 / 2,048 = 16$. Alternative calculation using K-units: - Single chip capacity = $2^{12} \times 4$ bits = $4096 \times 0.5$ bytes = 2 KB. - Total required = 32 KB. - Chips required = $32 \text{ KB} / 2 \text{ KB} = 16$.

To determine which block is not common to both AM and FM receivers, we must analyze the architecture of the Superheterodyne receiver, which is the standard for both modulation types: 1. **RF Amplifier (Option a):** Both AM and FM receivers use an RF amplifier at the front end to provide initial amplification and selectivity to the weak incoming signal. 2. **Mixer (Option b):** Both AM and FM receivers use a mixer to convert the incoming RF signal to a fixed Intermediate Frequency (IF) by mixing it with a local oscillator signal. 3. **IF Amplifier (Option d):** Both AM and FM receivers utilize IF amplifiers to provide the bulk of the receiver's gain and selectivity before the signal reaches the detector. 4. **Slope Detector (Option c):** A slope detector is a specific type of frequency-to-amplitude converter used to demodulate FM signals by converting frequency variations into amplitude variations (which can then be processed by an envelope detector). While it is used in some simple FM receivers, it is NOT used in AM receivers. AM receivers use envelope detectors or synchronous detectors to extract the message signal from the amplitude variations. Therefore, the slope detector is specific to FM (or used as a crude FM demodulator) and is not a common block shared by both AM and FM receiver architectures.

In microwave frequency ranges (typically 1 GHz to 300 GHz), coaxial cables suffer from significant signal loss. This is primarily due to two factors: 1) Dielectric loss, where the insulating material between the inner and outer conductors absorbs energy, and 2) Skin effect, where the current flows only on the surface of the conductor, increasing the effective resistance as frequency increases. Because attenuation increases proportionally with frequency, coaxial cables are impractical for long-distance microwave transmission, leading to the use of waveguides or optical fibers instead. Regarding other options: - 'Low selectivity' (a) is a characteristic of filters or receivers, not a transmission medium. - 'Low distortion' (b) would be an advantage, not a disadvantage. - 'High sensitivity' (d) is generally a property of sensors or receivers, not a cable's inherent disadvantage in signal transport.

To find the power in Watts from a value given in dBm, we use the standard formula: Power (dBm) = 10 * log10(P / 1mW) Given: Power = -90 dBm Step 1: Set up the equation: -90 = 10 * log10(P / 1mW) Step 2: Divide both sides by 10: -9 = log10(P / 1mW) Step 3: Convert from logarithmic to exponential form: 10^(-9) = P / 1mW Step 4: Solve for P: P = 10^(-9) * 1mW Since 1mW = 10^(-3) Watts: P = 10^(-9) * 10^(-3) Watts P = 10^(-12) Watts Step 5: Identify the metric prefix for 10^(-12): 10^(-12) Watts is equal to 1 picowatt (1 pW). Comparing this to the options: - Option (a) 1pW is correct. - Option (b) 1mW corresponds to 0 dBm. - Option (c) 1W corresponds to 30 dBm. - Option (d) 10W corresponds to 40 dBm.

A Traveling Wave Tube (TWT) is a specialized vacuum tube used to amplify radio frequency (RF) signals in the microwave range. The efficiency of a TWT is defined as the ratio of the RF output power to the DC beam power. 1. **Mechanism**: In a TWT, energy is transferred from the electron beam to the RF wave through a process of bunching. However, not all electrons in the beam contribute equally to the amplification; some electrons remain 'out of phase' or are not effectively bunched, meaning a significant portion of the DC beam power is wasted as heat. 2. **Typical Values**: For a standard TWT operating in a linear mode, the efficiency is relatively low, typically ranging from 10% to 20%. When operated in saturation (non-linear mode), the efficiency can increase, generally peaking between 30% and 40% for conventional tubes. 3. **Comparison**: While advanced TWTs (like those using depressed collectors) can achieve higher efficiencies, the 'typical' range cited in standard microwave engineering textbooks (such as Samuel Liao or Pozar) for a general TWT amplifier is 10% to 40%. Therefore, options a, b, and c are incorrect as they overestimate the typical efficiency of a standard TWT.

In the 8085 microprocessor, different interrupts have different triggering mechanisms: 1. **RST 7.5**: This interrupt is unique because it is both edge-triggered and level-sensitive. It is triggered by a positive-going edge (rising edge) of the signal, but the internal circuitry requires the signal to be at a high level to be recognized. Specifically, it is a positive edge-triggered interrupt that is latched internally. 2. **RST 5.5 and RST 6.5**: These are purely level-sensitive interrupts. The signal must be held low (active low) until the processor acknowledges the interrupt. 3. **TRAP**: This is a non-maskable interrupt that is both edge and level sensitive (similar to RST 7.5, it is triggered by a rising edge and then checked for level), but in the context of standard 8085 examination questions, RST 7.5 is the classic example of the 'edge-triggered' interrupt that requires level verification. However, technically TRAP is also both. Between the options provided in standard academic contexts for 8085, RST 7.5 is the primary answer for 'edge-triggered' behavior combined with level requirements. 4. **INTR**: This is a purely level-sensitive interrupt. The processor continues to poll the INTR pin until it is sampled as low during an instruction cycle. Therefore, RST 7.5 is the correct choice as it is the most distinct example of an edge-triggered interrupt that is also sensitive to the level for its latching mechanism.

The Voltage Standing Wave Ratio (VSWR) is related to the reflection coefficient (Γ) by the following formula: VSWR = (1 + |Γ|) / (1 - |Γ|). Given that the reflection coefficient Γ = 1/5, we substitute this value into the formula: VSWR = (1 + 1/5) / (1 - 1/5). Simplifying the numerator: 1 + 1/5 = 6/5. Simplifying the denominator: 1 - 1/5 = 4/5. Therefore, VSWR = (6/5) / (4/5) = 6/4 = 3/2. Thus, option (a) is correct. Options (b), (c), and (d) are incorrect as they do not satisfy the mathematical relationship between the reflection coefficient and VSWR.

Option C is correct: CARRY flag will be set to 1, ZERO flag to 0.

In C programming, the declaration of pointers and arrays is governed by operator precedence. The subscript operator [] has higher precedence than the dereference operator *. 1. Option (b) 'int (*P)[20];': The parentheses force the compiler to evaluate the '*' first. This tells the compiler that P is a pointer. The [20] then indicates that P points to an array of 20 integers. This is the correct syntax for a 'pointer to an array'. 2. Option (a) 'int *P[20];': Due to operator precedence, the [20] is evaluated first. This declares P as an array of 20 elements, where each element is a pointer to an integer (int *). This is known as an 'array of pointers'. 3. Option (c) 'int *(P[20]);': The parentheses around P[20] do not change the precedence of the subscript operator over the pointer operator. This is functionally equivalent to option (a), declaring an array of 20 pointers. 4. Option (d) 'int P*[20];': This is syntactically incorrect in C and will result in a compilation error.

In the Pascal programming language, formal parameters in procedures and functions can be categorized into four distinct classes based on how they are passed and used: 1. **Value Parameters**: The actual parameter is copied into the formal parameter. Changes made to the parameter inside the procedure/function do not affect the original variable (Call-by-Value). 2. **Variable Parameters (var parameters)**: The formal parameter acts as an alias for the actual parameter. Changes made inside the procedure/function directly affect the original variable (Call-by-Reference). 3. **Procedure Parameters**: Pascal allows procedures to be passed as arguments to other procedures or functions, enabling higher-order programming. 4. **Function Parameters**: Similarly, functions can be passed as arguments to other procedures or functions. Option (a) is incomplete as it only lists the most common data-passing modes. Option (b) and (d) are also incomplete. Option (c) comprehensively lists all four classes of formal parameters supported by the language specification.

In microprocessor architecture, there are two primary methods for interfacing I/O devices: Memory-Mapped I/O and I/O-Mapped I/O (also known as Isolated I/O). 1. **I/O Mapped I/O**: In this system, the CPU uses a separate address space for I/O devices, distinct from the memory address space. This is typically achieved using specific instructions like 'IN' and 'OUT'. In standard 8-bit microprocessors (such as the Intel 8085), the I/O address bus is 8 bits wide, meaning the CPU can address up to 256 (2^8) unique I/O ports. Therefore, each device is identified by an 8-bit port number. 2. **Memory Mapped I/O**: In this system, I/O devices are treated as memory locations. They share the same address space as the RAM/ROM, meaning they would use a 16-bit address (in the case of an 8085) or larger, depending on the architecture. Comparing the options: - Option (a) is incorrect because an instruction is the command to perform an action, not the identifier for a device. - Option (b) is incorrect because 'buffer number' is not the standard terminology for device identification in I/O mapping. - Option (c) is incorrect because 16-bit addresses are typically used for memory mapping in 8-bit processors, not for isolated I/O mapping. - Option (d) is correct as it describes the standard 8-bit port addressing used in I/O mapped systems for classic microprocessors.