Question 1

In data communications, ________ transmission uses a single conductor (plus a reference/ground) to send bits one after another over time.

Accepted Answer

Introduction / Context: Communication links move data as electrical signals. Two fundamental strategies exist: serial and parallel. Knowing which one uses a single data path is essential for understanding interfaces like UART, SPI, and USB. Given Data / Assumptions: A single conductor plus a reference (ground) is typical for one data line. Bits can be transmitted sequentially (serial) or simultaneously on multiple lines (parallel). We are identifying the transmission mode that fits “one conductor” carrying data bits over time. Concept / Approach: Serial transmission sends bits sequentially over one data line, often with a clock or embedded timing. Parallel transmission uses multiple conductors (one per bit or group of bits). The phrase “single conductor is used” aligns with serial data transport. Step-by-Step Solution: Match definition: one wire carries sequential bits → serial.Exclude modes that describe data type (digital, binary) rather than topology.Ignore unrelated term “automatic.”Select serial as the precise transmission mode. Verification / Alternative check: Standards such as RS-232 (with a dedicated TX line) and single-wire protocols exemplify serial transmission over minimal conductors. Why Other Options Are Wrong: digital: describes the nature of signals, not the number of conductors. automatic: not a transmission topology. binary: describes symbol set (0/1) rather than wiring method. Common Pitfalls: Assuming serial always means one total wire; practical links may use additional lines for ground, clock, or control, but only one primary data conductor is needed for serial data flow. Final Answer: serial

Question 2

Choose the correct statement: In ________, quantities are not represented by continuously variable indicators but by discrete symbols (for example, 0 and 1).

Accepted Answer

Introduction / Context: Information can be represented in continuous or discrete ways. This distinction underlies the difference between analog and digital systems, with implications for noise immunity, storage, and processing. Given Data / Assumptions: Analog uses continuous ranges of values. Digital uses discrete symbols, typically binary digits 0 and 1. We are choosing which representation is non-continuous. Concept / Approach: Digital representation maps quantities to a finite set of symbols. Each symbol can be transmitted, stored, and processed with robustness to noise through thresholds and error correction. Analog representation, by contrast, maps directly to continuously varying voltages or currents. Step-by-Step Solution: Identify key phrase: “not represented by continuously variable indicators.”This aligns with discrete (digital) representation.Select digital representation accordingly.Confirm that analog is the opposite case (continuous). Verification / Alternative check: Digital communication systems encode voice, image, and data into bits precisely because discrete symbols are easier to regenerate and store. Why Other Options Are Wrong: analog representation: explicitly continuous, not discrete. signal representation: too broad and not specific to discreteness. computer representation: computers use digital internally, but the phrase is vague and not a formal category. Common Pitfalls: Equating “digital” with “perfect”; while discrete, digital still contends with quantization noise and implementation limits. Final Answer: digital representation

Question 3

Central Processing Unit (CPU): The CPU contains all the circuitry primarily responsible for ________ in a stored-program computer.

Accepted Answer

Introduction / Context: The CPU is the computational heart of a computer. In the von Neumann model, it executes a cycle that repeatedly brings in instructions and performs the operations they specify. Knowing this role clarifies the CPU’s boundary relative to memory and peripherals. Given Data / Assumptions: A stored-program architecture is assumed. Instructions and data reside in memory. The CPU implements the fetch–decode–execute cycle. Concept / Approach: The CPU orchestrates fetching instructions from memory, decoding their meaning (operation, operands, addressing modes), and executing them via arithmetic logic unit (ALU), registers, and control logic. While a CPU can temporarily hold data in registers and caches, bulk data storage is the role of memory and secondary storage, not the CPU. Step-by-Step Solution: Identify the CPU’s core loop: fetch → decode → execute.Map each step to circuitry: control unit (sequencing), ALU (compute), registers (operands), buses (transfer).Select the phrase that best summarizes this role: “fetching and interpreting instructions.”Exclude answers that describe peripheral or system functions. Verification / Alternative check: Architecture textbooks emphasize instruction processing as the CPU’s defining job; timing and networking are handled by clocks and network stacks elsewhere. Why Other Options Are Wrong: storing data: main memory and disks handle storage; CPU registers are transient. keeping track of time: usually a real-time clock or system timer peripheral. Internet operations: involve NICs, stacks, and OS, not the CPU alone. Common Pitfalls: Assuming caches make the CPU a storage device; caches are small, transient, and support instruction/data processing rather than long-term storage. Final Answer: fetching and interpreting instructions

Question 4

Negative logic convention: In a negative-logic system, which voltage region corresponds to a logical HIGH (logic 1) level?

Accepted Answer

Introduction / Context: Digital systems can define logic levels using either positive or negative logic conventions. In positive logic, a higher voltage represents logic 1; in negative logic, the mapping is inverted. This question ensures clarity about what “logic HIGH” means under negative logic. Given Data / Assumptions: Two-level digital system with defined valid LOW and HIGH voltage regions. Negative logic definition: logic 1 is assigned to the lower voltage region. We identify which voltage region corresponds to logical HIGH (logic 1) in negative logic. Concept / Approach: Logic conventions are labelings applied to the same physical voltage windows. Negative logic simply swaps the semantic labels: low voltage corresponds to logic 1 (HIGH), and high voltage corresponds to logic 0 (LOW). The electronics do not change; only the interpretation does. Step-by-Step Solution: Recall positive logic: high voltage → 1, low voltage → 0.Apply negative logic: invert the assignment.Thus, the lower voltage region is labeled as logical HIGH (1) under negative logic.Choose LOW as the correct voltage region for logic 1 in this convention. Verification / Alternative check: Truth tables can be reinterpreted by swapping labels; hardware remains identical while logical naming changes, confirming the mapping. Why Other Options Are Wrong: HIGH: that is the positive-logic mapping, not negative logic. off: not a standard logic-level designation; ambiguous. uncertain: implies the indeterminate region, not a defined logic level. Common Pitfalls: Equating “HIGH” with “high voltage” universally; always check whether the system uses positive or negative logic before labeling signals. Final Answer: LOW

Question 5

Memory element basics: A logic circuit capable of storing exactly one bit of information (0 or 1) is called a ________.

Accepted Answer

Introduction / Context: Sequential logic relies on elements that retain state across time. The smallest such storage element in synchronous digital design stores a single bit and is used to build registers, counters, and memory arrays. Given Data / Assumptions: The device stores exactly one binary value. Used in synchronous and asynchronous systems. Standard digital design terminology is assumed. Concept / Approach: A flip-flop is a bistable multivibrator with two stable states representing 0 and 1. Edge-triggered types (D, JK, T) capture input on a clock transition and hold it until the next triggering event. Latches are level-sensitive relatives; both serve as 1-bit storage, but “flip-flop” is the canonical answer for clocked one-bit storage. Step-by-Step Solution: Identify requirement: store one bit reliably.Match device: flip-flop fulfills this role; gates do not store state, counters store multiple bits, converters translate codes.Choose flip-flop.Recognize various types (D, JK, T) all meet the definition. Verification / Alternative check: Register files are arrays of flip-flops; a 32-bit register uses 32 flip-flops, confirming the one-bit-per-device mapping. Why Other Options Are Wrong: counter: comprises multiple flip-flops to store multi-bit counts. gate: combinational element with no memory (ideal model). code converter: transforms representations (e.g., BCD to seven-segment) rather than storing state. Common Pitfalls: Conflating latches and flip-flops. Both store one bit; however, most curricula reserve “flip-flop” for edge-triggered elements. Final Answer: flip-flop

Question 6

Embedded control: A microcontroller would not typically be used in which of the following applications?

Accepted Answer

Introduction / Context: Microcontrollers integrate a CPU, memory, and peripherals on one chip for embedded control tasks. They are ubiquitous in consumer electronics and automobiles. This question checks recognition of where such embedded control is not typically necessary. Given Data / Assumptions: Typical microcontroller roles: sensing, timing, control loops, user interfaces. Devices requiring programmable logic, timing, and I/O are candidates. We compare modern electronic systems to a traditional mechanical timepiece. Concept / Approach: VCRs, ignition systems, and antilock brakes all require precise control and real-time decision making, making microcontrollers ideal. A traditional grandfather clock operates mechanically using weights, pendulums, and escapements and does not require electronics. While a modernized clock could use one, the conventional example is mechanical and thus the best choice. Step-by-Step Solution: List candidates that demand sensing/actuation: VCR (motors, UI), ignition (timing), ABS (feedback control).Identify the outlier that is inherently mechanical: grandfather clock.Choose grandfather clock as not requiring a microcontroller.Note exception: only if electronically modernized would it need one. Verification / Alternative check: Automotive ECUs and ABS controllers are standard microcontroller applications; consumer video devices have long used embedded controllers. Why Other Options Are Wrong: VCR: needs motor control, display driving, and user input handling. automobile ignition system: requires precise timing and sensor input processing. antilock brakes: closed-loop control with sensors and actuators. Common Pitfalls: Assuming any clock is electronic. The term “grandfather clock” generally refers to a mechanical longcase clock. Final Answer: grandfather clock

Question 7

Signal integrity after digitization: Once an analog signal is digitized correctly, the information it contains does not ________ as it is processed and relayed through digital systems.

Accepted Answer

Introduction / Context: A key advantage of digital systems is that discrete symbols (bits) can be regenerated exactly, preventing cumulative quality loss that plagues analog processing chains. This property underlies robust storage, networking, and error-corrected communications. Given Data / Assumptions: The original analog signal has been sampled and quantized within the system’s specifications. Digital processing uses thresholds and regeneration to restore ideal levels. Error detection/correction can be applied to maintain integrity. Concept / Approach: In a properly designed digital pipeline, signals are re-timed and re-leveled, so noise does not accumulate from stage to stage. Therefore the information does not deteriorate during processing; instead, it remains intact as long as errors stay below correctable thresholds. Step-by-Step Solution: Compare analog vs digital chains: analog suffers gradual SNR loss; digital reconstructs clean logic levels.Identify the intended property: no cumulative degradation of content in digital.Select the verb that fits: “deteriorate.”Note that compression is optional and can be lossless or lossy; it is not implied. Verification / Alternative check: Digital repeaters in networks demonstrate regeneration; storage copies are identical bit-for-bit, avoiding generational loss present in analog tape dubbing. Why Other Options Are Wrong: complain/stiffen: nonsensical in this context. compress: orthogonal concept; digital data may or may not be compressed. Common Pitfalls: Believing digital is immune to all errors. Catastrophic errors can occur when noise exceeds margins, but under normal margins, information integrity is preserved. Final Answer: deteriorate

Question 8

Logic-level naming in positive logic: In a standard positive-logic system, the lower valid input voltage region is termed the ________ level.

Accepted Answer

Introduction / Context: Digital logic specifications define valid voltage regions for interpreting binary states. In positive logic, conventions label the higher voltage region as logic 1 (HIGH) and the lower region as logic 0 (LOW). This question confirms your grasp of that terminology. Given Data / Assumptions: Positive-logic convention is assumed. Two non-overlapping valid regions exist, with an undefined region between them. We are naming the lower valid region. Concept / Approach: By definition, positive logic assigns logic 1 to higher voltages and logic 0 to lower voltages. Therefore, the lower valid region is called the LOW level and represents logic 0. Datasheets specify VIL (maximum low input voltage) and VIH (minimum high input voltage) to guarantee correct recognition. Step-by-Step Solution: Recall mapping: high voltage → HIGH (1), low voltage → LOW (0).Identify the region asked: the lower valid region.Name it according to convention: LOW level.Confirm via datasheet parameters (VIL/VIH). Verification / Alternative check: TTL/CMOS families publish input-level tables showing VIL max and VIH min; the lower region is consistently labeled LOW. Why Other Options Are Wrong: HIGH: refers to the upper region. off: ambiguous; not a standard logic-level name. unacceptable: describes the undefined region, not a valid level. Common Pitfalls: Confusing output voltage levels with input threshold specifications; while related, both use the same HIGH/LOW naming for valid regions. Final Answer: LOW

Question 9

Measurement styles: A continually variable, proportional indicator (for example, a smoothly varying needle or voltage) is an ________ representation.

Accepted Answer

Introduction / Context: Signals and measurements can be represented as continuous values or discrete steps. This distinction defines analog versus digital approaches and affects sensor design, display technology, and signal processing methods. Given Data / Assumptions: The indicator changes smoothly in proportion to the measured quantity. Examples include needles on a meter, continuous voltage levels, and varying light intensity. We need the correct classification term. Concept / Approach: An analog representation uses a continuously variable physical quantity to represent information. A digital representation instead uses discrete levels or symbols. A proportional, smoothly varying indicator therefore fits the analog definition precisely. Step-by-Step Solution: Identify key clue: “continually variable” and “proportional.”Map to concept: continuous variation → analog.Eliminate terms unrelated to continuity (digital, decimal, unconstitutional).Select analog as the correct representation type. Verification / Alternative check: Classic moving-coil meters provide analog readouts; modern digital multimeters convert to digital for display but may also present bar graphs that emulate analog style. Why Other Options Are Wrong: decimal: a base for numbers, not a representation style of continuity. digital: discrete steps rather than continuous variation. unconstitutional: irrelevant to engineering terminology. Common Pitfalls: Confusing “analog” with “old” or “less accurate.” Analog can be highly accurate; the distinction concerns continuity versus discreteness, not quality. Final Answer: analog

Question 10

TTL input thresholds and undefined region In standard TTL (transistor–transistor logic) families, which input-voltage range is considered invalid or undefined for reliable logic interpretation?

Accepted Answer

Introduction / Context: Digital inputs in TTL (transistor–transistor logic) operate correctly only when the applied voltage clearly corresponds to a logic LOW or a logic HIGH. This question tests your recall of the formal LOW, HIGH, and undefined (invalid) ranges for classic TTL input thresholds. Given Data / Assumptions: Family considered: standard TTL logic conventions. Typical guaranteed thresholds: VIL(max) = 0.8 V (upper bound for LOW) and VIH(min) = 2.0 V (lower bound for HIGH). Supply assumed near 5 V, which is typical for TTL. Concept / Approach: A digital input is recognized as LOW if the voltage is at or below VIL(max). It is recognized as HIGH if the voltage is at or above VIH(min). Any input that lies between these two limits is not guaranteed to be interpreted consistently; it falls into the invalid or undefined region. Designers avoid operating inputs in this middle band to ensure noise margin and reliable switching. Step-by-Step Solution: Identify VIL(max) for TTL inputs: 0.8 V.Identify VIH(min) for TTL inputs: 2.0 V.Define the undefined region as the voltages strictly between 0.8 V and 2.0 V.Conclude the invalid range is 0.8 to 2.0 V. Verification / Alternative check: TTL datasheets list guaranteed input logic-level thresholds with noise margins. The gap between 0.8 V and 2.0 V provides tolerance to noise and device variation. Inputs in this band can cause oscillation or indeterminate logic state. Why Other Options Are Wrong: 0 to 0.8 V: This is the valid LOW region, not invalid. 1.2 to 1.6 V: This interval lies inside the undefined range but does not name the whole invalid range. 2.0 to 5.0 V: This is the valid HIGH region for TTL inputs. Not applicable: Threshold specifications always apply; the undefined band is real. Common Pitfalls: Confusing CMOS input thresholds (which depend on VCC fraction) with fixed TTL thresholds; assuming any mid-level value will be “interpreted somehow,” which risks metastability or chatter. Final Answer: 0.8 to 2.0 V

Question 11

CPU composition basics In computer organization, the control unit and the arithmetic/logic unit are often grouped together and referred to collectively as the ________.

Accepted Answer

Introduction / Context: Foundational computer architecture bundles the control unit (sequencing and control of operations) with the arithmetic/logic unit (ALU) that performs integer arithmetic and Boolean operations. Together, they are historically known as the central processing unit (CPU). This item checks basic terminology used across textbooks and datasheets. Given Data / Assumptions: Control unit orchestrates instruction fetch, decode, and control signals. ALU executes arithmetic and logical functions on data. Memory and I/O are separate subsystems interfacing with the CPU. Concept / Approach: The CPU is the heart of the computer, combining the control logic that interprets instructions with the ALU that manipulates data. Modern microarchitectures integrate additional blocks (register files, floating-point units, caches), but the classical definition remains: CPU = control unit + ALU (plus registers). Step-by-Step Solution: Identify the two named blocks: control unit and ALU.Recall the classical grouping: these together form the CPU.Select the option that names this combined entity: central processing unit.Confirm that other options name broader or narrower concepts. Verification / Alternative check: Block diagrams in architecture texts consistently show CPU comprising control + ALU, typically with registers and internal buses. Microprocessor datasheets refer to these as internal CPU components. Why Other Options Are Wrong: Inputs and outputs: These are peripheral interfaces, not the CPU. Microcomputer: Includes CPU, memory, and I/O on a board/system; broader than the asked grouping. Arithmetic/logic unit: Only one of the two parts; control unit is missing. Processing core only: Informal term; still essentially the CPU but the correct, standard name is CPU. Common Pitfalls: Equating microprocessor (a chip) with microcomputer (a complete system), or forgetting that the CPU also requires registers and control paths to operate the ALU effectively. Final Answer: central processing unit

Question 12

Number systems refresher The base-10 (decimal) number system is composed of how many distinct symbols (digits)?

Accepted Answer

Introduction / Context: Understanding different bases is central to digital electronics and computing. Decimal (base 10) is the everyday system; binary (base 2), octal (base 8), and hexadecimal (base 16) are used heavily in engineering. This question checks recall of the decimal system’s symbol count. Given Data / Assumptions: Decimal uses symbols 0 through 9. Base b systems use exactly b distinct digit symbols. No extended notation (like letters for digits beyond 9) applies to base 10. Concept / Approach: By definition, a base-10 system has ten unique symbols. Positional notation means each position weight is a power of 10, and digits 0–9 are used to represent quantities at each position. Step-by-Step Solution: Recall base-10 digits: 0,1,2,3,4,5,6,7,8,9.Count the set: there are 10 symbols.Match with the option “10.”Confirm other options correspond to bases 2, 8, and 16 respectively. Verification / Alternative check: Conversion methods (e.g., repeated division) and place-value representation rely on exactly ten symbols in decimal arithmetic; elementary math supports this definition unequivocally. Why Other Options Are Wrong: 2: Binary, not decimal. 8: Octal, not decimal. 16: Hexadecimal, not decimal. 20: Not a standard base in common digital practice and certainly not decimal. Common Pitfalls: Confusing the count of symbols with the largest symbol value; remember the highest digit is 9, but the number of symbols is 10 total. Final Answer: 10

Question 13

Data transfer modes in digital systems Systems that move multiple bits at the same instant across several conductors are said to transfer data ________.

Accepted Answer

Introduction / Context: Digital designs use two fundamental data transfer modes: serial and parallel. Correctly identifying the mode from its description is essential for understanding bus design, throughput, and cabling trade-offs in computers, microcontrollers, and communication links. Given Data / Assumptions: Parallel transfer uses multiple conductors to carry multiple bits simultaneously. Serial transfer uses one lane (or a differential pair) to send bits sequentially in time. “At the same instant” implies simultaneous multi-bit transfer. Concept / Approach: The phrase “move multiple bits at the same instant across several conductors” is the defining characteristic of parallel transfer. This is common on internal buses (e.g., an 8-bit data bus) where wiring cost and skew can be managed over short distances. Serial links dominate long-distance/high-speed connections where pin count must be minimized. Step-by-Step Solution: Identify key phrase: simultaneous multi-bit movement.Map this to parallel transfer by definition.Exclude serial because it is bit-by-bit over time.Select “in parallel.” Verification / Alternative check: Classic textbooks distinguish parallel (wider buses, higher instantaneous width) and serial (narrow link, serialized bits). Timing diagrams of parallel buses show several lines toggling in the same clock window for a word transfer. Why Other Options Are Wrong: Serially: Bits are not transferred simultaneously; they are sequenced. Sequentially: Ambiguous phrase; could apply to control steps, not to the physical transfer width. Both serially and sequentially: Mixes concepts; not the definition in the prompt. Asynchronously only: Synchronization is orthogonal to parallel/serial classification. Common Pitfalls: Confusing differential signaling (two wires) with parallel transfer; a differential pair still carries one serialized bit stream per pair. Final Answer: in parallel

Question 14

Waveform interpretation The combined view of related digital waveforms (for example, clock and data across time) is commonly referred to as a ________.

Accepted Answer

Introduction / Context: Digital designers visualize multiple signals together to understand their relationships—setup/hold, enable windows, bus transitions, and protocol events. The standard name for such a coordinated, time-aligned set of signal plots is a timing diagram. Given Data / Assumptions: Multiple signals shown against the same time axis. Interest lies in relative edges, durations, and overlaps. Typical sources: logic analyzer captures or hand-drawn specification charts. Concept / Approach: A timing diagram is a graphical representation of logical levels as functions of time, typically across several channels. It helps verify protocol sequencing, ensure that constraints (like setup and hold times) are satisfied, and communicate expected behavior between design and verification teams. Step-by-Step Solution: Identify that multiple waveforms are viewed together across a shared time axis.Recognize this collective, synchronized view as a timing diagram.Select the option that explicitly names “a timing diagram.”Confirm other terms fail to capture the standard nomenclature. Verification / Alternative check: Logic analyzers and EDA tools export “timing diagrams” for buses and protocols (SPI, I2C, memory buses), reinforcing the terminology in practice and documentation. Why Other Options Are Wrong: Simultaneous waveforms: Descriptive, not the established term. Two-phase waveforms: Describes a specific clocking style, not a general multi-signal view. Pulse waveforms: Too generic; any digital signal is a series of pulses. Event raster: Not a common digital design term. Common Pitfalls: Assuming timing diagrams show analog amplitude; they typically emphasize logic states and transitions, not precise analog voltage levels. Final Answer: a timing diagram

Question 15

Define demultiplexing In digital logic, demultiplexing is the function that ________.

Accepted Answer

Introduction / Context: Multiplexers (MUX) and demultiplexers (DEMUX) are fundamental routing elements in digital systems. Knowing the direction of signal selection—many-to-one versus one-to-many—is key when designing data paths, addressing memory banks, or steering control signals. Given Data / Assumptions: A multiplexer selects one of many inputs and forwards it to a single output. A demultiplexer takes one input and routes it to one of many outputs. Selection is controlled by binary select lines. Concept / Approach: Demultiplexing distributes a single input to multiple destinations based on select signals. Typical notation: 1-to-N. In contrast, multiplexing is N-to-1. Real devices may combine with latches or tristate drivers in buses; the core logical definition remains the same. Step-by-Step Solution: Clarify MUX vs. DEMUX directionality (N→1 vs. 1→N).Match “one input to several outputs” with demultiplexer behavior.Identify option describing this routing explicitly.Choose “switches logic from one input to any of several output lines.” Verification / Alternative check: Truth tables for 1-to-4 DEMUX show input D appearing at Y0–Y3 depending on select S1:S0, validating the definition. Why Other Options Are Wrong: Determines greatest input: This is a magnitude comparator task. Several inputs onto one output: That is a multiplexer. Converts a code: That is a decoder/encoder function. Stores data: That is memory or a latch/flip-flop function. Common Pitfalls: Confusing DEMUX with decoder; although related, a DEMUX also forwards the data signal, not just asserts a single line. Final Answer: switches logic from one input to any of several output lines

Question 16

Comparing binary numbers To determine which of two binary numbers is larger (>, =, <), the appropriate digital circuit to use is a ________.

Accepted Answer

Introduction / Context: Comparing two binary quantities is a recurring need in CPUs, ALUs, sorting hardware, and control logic. Dedicated magnitude comparators perform this function efficiently in combinational logic, providing outputs for A>B, A=B, and A Given Data / Assumptions: Inputs: two N-bit binary numbers A and B. Outputs: flags indicating greater-than, equal, or less-than. No sequencing or storage is required for pure comparison. Concept / Approach: A magnitude comparator evaluates bits from MSB to LSB, using logic to determine the first position where A and B differ and to propagate equality otherwise. ICs like the 74xx85 implement this in hardware and can be cascaded for wider words using carry-like cascade inputs/outputs. Step-by-Step Solution: Identify function needed: compare two binary numbers.Select circuit class: magnitude comparator (not an adder or storage element).Note it directly outputs greater/equal/less flags.Choose “magnitude comparator.” Verification / Alternative check: While subtraction (A−B) using an adder could infer comparison via sign/zero flags, a magnitude comparator provides the logic explicitly and is the standard component for this job. Why Other Options Are Wrong: Register: Stores data; does not compare. Adder: Can assist via subtraction, but is not the direct comparison circuit. Encoder: Maps many inputs to a coded output; unrelated. Binary counter: Sequences numbers; not a comparator. Common Pitfalls: Assuming arithmetic units are necessary for comparison; dedicated comparators save logic, timing, and design complexity. Final Answer: magnitude comparator

Question 17

Programming terminology The complete set of instructions that a computer executes to perform a task is called a(n) ________.

Accepted Answer

Introduction / Context: In computing, we distinguish between data, instructions, and the hardware that executes them. The term “program” denotes an ordered collection of instructions (and possibly data) arranged to achieve a specific outcome when executed by a processor or interpreter. Given Data / Assumptions: Instructions exist in a defined sequence. The computer can fetch, decode, and execute these instructions. Inputs/outputs are roles in I/O operations, not the instruction set itself. Concept / Approach: A program can be in machine language, assembly, or a high-level language compiled/interpreted into executable form. It encompasses control flow (branches, loops), data manipulation, and interactions with memory and peripherals to accomplish tasks from simple calculations to complex applications. Step-by-Step Solution: Identify that the question asks for the name of a sequence of instructions.Recall standard terminology: “program.”Eliminate options that represent roles (input/output) or hardware (control unit).Select “program.” Verification / Alternative check: Operating systems manage program execution via processes or tasks; development toolchains produce program binaries from source code, affirming the standard term. Why Other Options Are Wrong: Input/Output: These are data directions, not the instruction set. Control unit: Hardware that orchestrates execution; not the instruction sequence. Instruction opcode only: A single operation code cannot constitute a complete set. Common Pitfalls: Confusing “program” with “algorithm”: an algorithm is a method; a program is a concrete implementation in code executed by a computer. Final Answer: program

Question 18

Representing binary conveniently Besides binary itself, engineers commonly use other ________ to interpret or represent binary quantities for ease of reading and conversion.

Accepted Answer

Introduction / Context: Working directly with long binary strings is cumbersome. Engineers adopt alternative number systems that map neatly to binary groupings to make representation, debugging, and conversion faster and less error-prone. This question asks for that general category of representations. Given Data / Assumptions: Goal: human-friendly interpretation of binary values. Common choices: octal and hexadecimal, which align with 3-bit and 4-bit groupings. Context: digital electronics, firmware, and debugging tools. Concept / Approach: Octal (base 8) groups bits in threes; hexadecimal (base 16) groups bits in fours. These number systems provide compact notation while preserving a simple, exact mapping to binary. Conversions are straightforward and minimize transcription errors compared to raw binary strings. Step-by-Step Solution: Identify the problem: binary is verbose for humans.Choose a representation class: other number systems with convenient mapping.Name the general category: number systems (e.g., octal, hex).Confirm that the term matches the use case. Verification / Alternative check: Assembler listings, debuggers, and datasheets routinely show addresses and constants in hexadecimal because it compresses binary by a factor of four with trivial conversion. Why Other Options Are Wrong: Analog systems: Not a numeral representation. Digital systems: Overly broad; refers to entire classes of circuits/computers. Binary systems: This is the original system we are trying to represent more conveniently. Coding delays: Not a representation at all. Common Pitfalls: Assuming decimal is always convenient; while familiar, hexadecimal provides a tighter mapping to binary and is preferred for low-level work. Final Answer: number systems

Question 19

Latch-based storage devices Memory devices that store state using electronic latching circuits are called ________.

Accepted Answer

Introduction / Context: Digital storage can be realized using many technologies: capacitor charge in DRAM, floating gates in flash, magnetic domains in disks/tape, or bistable electronic latches. This question focuses on the class that relies on latching circuits to hold binary states. Given Data / Assumptions: A “latching circuit” is a bistable element (two stable states). Common implementations: SR latch, D latch, and edge-triggered flip-flops. Use cases: registers, counters, pipeline stages, small on-chip memories. Concept / Approach: A flip-flop is an edge-triggered bistable device built from cross-coupled gates that stores one bit reliably until changed by a clocked input. Arrays of flip-flops form registers and small register files. In contrast, DRAM stores charge on capacitors (needs refreshing) and is not “latching” in the same sense; magnetic tape is a magnetic medium, not an electronic latch. Step-by-Step Solution: Identify that the storage mechanism is an electronic latch.Map that to flip-flops (or latches) as the canonical bistable storage elements.Eliminate technologies based on capacitors, floating gates, or magnetic domains.Select “flip-flops.” Verification / Alternative check: Textbook register-transfer-level diagrams show registers as banks of D flip-flops, clearly using latching circuits to hold state between clock edges. Why Other Options Are Wrong: RAM: A broad category; much RAM (e.g., DRAM, SRAM) is not described purely as “latching circuits” in the general sense, and the term is too generic. Magnetic tape: Not electronic latching; it is a magnetic storage medium. DRAM: Stores charge on capacitors and requires refresh; not latch-based. Flash arrays: Use floating-gate transistors; not classic latching circuits. Common Pitfalls: Conflating SRAM (static RAM) with discrete flip-flops; while SRAM cells are bistable, the question uses the phrase “electronic latching circuits” typically referring to flip-flops in logic design contexts. Final Answer: flip-flops

Question 20

In digital electronics, what is the highest-value seven-bit (7-bit) binary number when interpreted as an unsigned quantity?

Accepted Answer

Introduction: Seven-bit binary numbers are common in legacy character encodings and basic digital counters. The question asks for the highest-value number representable with 7 bits when interpreted as an unsigned quantity (no sign bit). Given Data / Assumptions: Unsigned binary representation with exactly 7 bits. Bit positions range from b6 (MSB) to b0 (LSB). No sign or bias; pure base-2 magnitude. Concept / Approach: For an n-bit unsigned integer, the minimum value is 0 and the maximum value is 2^n - 1. Setting all n bits to 1 yields the maximum value. For n = 7, the maximum is 2^7 - 1 = 128 - 1 = 127. Step-by-Step Solution: Let n = 7.Max unsigned value = 2^n - 1.Compute 2^7 = 128.Subtract 1: 128 - 1 = 127.Binary pattern 1111111₂ equals 127 in decimal. Verification / Alternative check: Write the place values: 64 + 32 + 16 + 8 + 4 + 2 + 1 = 127. This matches 2^7 - 1. Why Other Options Are Wrong: 128: Requires 8 bits (10000000₂); exceeds 7-bit range. 126: One less than maximum; binary 1111110₂. 125: Two less than maximum; binary 1111101₂. Common Pitfalls: Confusing signed with unsigned. In signed 7-bit (two's complement is defined for 8-bit, not 7), ranges differ. Here we clearly use unsigned 7-bit magnitude. Final Answer: 127

Digital Concepts Questions