GK: Class 12 General Q&A · Page 21
3,658 free answers on GK (General) for Class 12 students, across CBSE, ICSE and State boards.
Question & Answer
Questions
- GeneralClass 12All
What is the TSA formula for a hollow sphere
The Total Surface Area (TSA) formula for a hollow sphere (spherical shell) with inner radius r₁ and outer radius r₂ is TSA = 4πr₂² + 4πr₁² = 4π(r₂² + r₁²), which accounts for both the outer sphere surface and the inner sphere surface. This formula recognizes that a hollow sphere has two distinct surfaces requiring measurement—the larger outer surface and the smaller inner surface—and TSA includes both since they're both part of the object's complete bo
- GeneralClass 12All
Why are CSA and TSA of sphere the same
The CSA (Curved Surface Area) and TSA (Total Surface Area) of a sphere are identical because a sphere consists entirely of one continuous curved surface with absolutely no flat surfaces, edges, bases, or caps—there are no additional surfaces to add when calculating total surface area. Unlike cylinders (which have flat circular ends), cones (which have flat circular bases), or prisms (which have flat faces), a sphere is pure curved surface extending uniformly in all directions from its c
- GeneralClass 12All
How to calculate cross sectional area of sphere
The cross-sectional area of a sphere taken through any plane passing through or intersecting the sphere depends on where the cut is made. The maximum cross-sectional area occurs when cutting through the sphere's center (equatorial cut), producing a circle with radius equal to the sphere's radius r, giving a cross-sectional area of πr²—the area of the largest possible circular slice. Cuts made at other positions (not through center) produce smaller circular cross-sections with ra
- GeneralClass 12All
What is the CSA of a spherical shell
A spherical shell (hollow sphere with inner radius r₁ and outer radius r₂) has two curved surfaces—the outer sphere surface and the inner sphere surface—making the total CSA = 4πr₂² + 4πr₁², which can be factored as 4π(r₂² + r₁²). This formula adds the surface area of the larger outer sphere (4πr₂²) and the smaller inner sphere (4πr₁²) since both surfaces exist and contribute to the total curved surface area of the hollow shell. <p
- GeneralClass 12All
What are the 20 formulas in maths
Listing exactly "20 formulas in maths" is somewhat arbitrary since mathematics contains thousands of important formulas across different topics, but here are 20 fundamental formulas commonly taught from elementary through high school: (1) Area of rectangle = length × width, (2) Area of triangle = ½ × base × height, (3) Area of circle = πr², (4) Circumference = 2πr, (5) Volume of cuboid = l × b × h, (6) Volume of cylinder = πr²h, (7) Volu
- GeneralClass 12All
What is p/v profit volume ratio
The P/V ratio (Profit-Volume ratio), also called contribution margin ratio, is a financial metric expressing the relationship between contribution (sales minus variable costs) and sales revenue, typically written as: P/V Ratio = (Contribution / Sales) × 100, or equivalently, (Sales - Variable Costs) / Sales × 100. This ratio indicates what percentage of each sales dollar contributes toward covering fixed costs and generating profit, making it crucial for cost-volume-profit (CVP) a
- GeneralClass 12All
Why is cell size limited
Cell size is limited primarily by the surface area to volume ratio (SA/V ratio), which decreases as cells grow larger, eventually making it impossible for the cell to exchange materials (nutrients, oxygen, waste, signaling molecules) efficiently enough through its membrane to support its internal volume. As a cell's radius increases, its volume grows proportionally to r³ while surface area grows only proportionally to r², meaning larger cells have less surface area relative to their
- GeneralClass 12All
Why do people use CSV files
People use CSV (Comma-Separated Values) files because they provide a simple, universal, human-readable format for storing and exchanging tabular data that works across virtually all software platforms, programming languages, and operating systems without requiring proprietary applications. CSV's plain-text structure makes files lightweight, easy to create and edit manually if needed, version-control-friendly (changes show clearly in text diffs), and compatible with everything from Excel and G
- GeneralClass 12All
What does CSA mean in tech
In technology contexts, CSA most commonly stands for Cloud Security Alliance (an industry organization promoting best practices for secure cloud computing), Cross-Sectional Area (in hardware engineering and physics), Carry-Save Adder (in digital circuit design), or Certificate Signing Request (in cybersecurity and cryptography). The specific meaning depends heavily on the technical domain and context. Cloud Security Alliance is a prominent non-profit organization providing security gu
- GeneralClass 12All
What is a computer validation system
A computer validation system (often called Computer System Validation or CSV) is a documented process used primarily in regulated industries like pharmaceuticals, medical devices, and biotechnology to establish and maintain evidence that computerized systems consistently perform as intended and produce accurate, reliable results. CSV ensures that software, hardware, and associated processes meet predetermined specifications and regulatory requirements, particularly those set by agencies like
- GeneralClass 12All
How does a carry-lookahead adder work
A carry-lookahead adder (CLA) is a fast binary addition circuit that eliminates the sequential carry propagation delay of ripple carry adders by using additional logic to predict carries in advance, calculating them in parallel based on the original input bits rather than waiting for previous stages to complete. The CLA achieves this speed by introducing two concepts for each bit position: generate (G) and propagate (P). A position "generates" a carry if both input bits are 1 (Gi = Ai AND Bi)
- GeneralClass 12All
Are there faster adder designs
Yes, several adder designs are faster than basic ripple carry adders, each offering different trade-offs between speed, circuit complexity, power consumption, and chip area. Beyond carry-lookahead adders (CLAs), major fast adder architectures include: Carry-Select Adders, which calculate results for both possible carry-in values in parallel and select the correct result using multiplexers once the actual carry arrives; Carry-Skip Adders (or carry-bypass adders), which detect when a group of b
- GeneralClass 12All
What does the term "summation" mean
Summation means the process or operation of adding multiple numbers, quantities, or values together to obtain their total, represented mathematically by the sum. The term comes from the Latin "summa" meaning "highest" or "total," referring to the aggregate result of addition. In mathematics, summation specifically refers to adding a sequence of numbers or expressions, often compactly notated using the summation symbol Σ (capital sigma). Summation appears across all levels of mat
- GeneralClass 12All
What does zeta mean in math
In mathematics, zeta (ζ, the lowercase Greek letter) most famously refers to the Riemann zeta function, one of the most important functions in number theory and one deeply connected to the distribution of prime numbers. The Riemann zeta function is defined as ζ(s) = ∑(n=1 to ∞) 1/n^s for complex numbers s with real part greater than 1, and can be analytically continued to other complex values. This function has profound significance because its zeros (values where ζ(s
- GeneralClass 12All
What is the hardest math sum
The concept of "hardest math sum" is ambiguous because "sum" technically means addition result, but people might mean "hardest math problem." If referring to difficult addition problems, arbitrarily large numbers can be added (adding two trillion-digit numbers is computationally intensive but mathematically straightforward). However, if "sum" refers broadly to summation problems in advanced mathematics, some extraordinarily difficult challenges include: evaluating certain infinite series wher
- GeneralClass 12All
What is a binary parallel adder
A binary parallel adder is a digital circuit that adds two multi-bit binary numbers simultaneously by processing all bit positions in parallel rather than sequentially. Unlike serial adders that process bits one at a time, parallel adders use multiple full adder circuits operating concurrently—one full adder for each bit position—allowing much faster addition since bits are calculated simultaneously with carries propagating through the circuit structure. The most basic par
- GeneralClass 12All
What is the answer to 6 ÷ 2(1+2)
The expression 6 ÷ 2(1+2) evaluates to 9 using proper order of operations. Following PEMDAS/BODMAS (Parentheses/Brackets first, then Exponents/Orders, then Multiplication and Division left-to-right, then Addition and Subtraction left-to-right), you first solve the parentheses: (1+2) = 3. The expression becomes 6 ÷ 2 × 3. Crucially, multiplication and division have equal priority and are evaluated strictly left-to-right, so you perform 6 ÷ 2 = 3 first, then 3 ×
- GeneralClass 12All
How many logic gates are in a CPU
A modern CPU contains billions of logic gates—contemporary processors like Intel's 13th generation Core processors contain approximately 25-30 billion transistors, and since each basic logic gate consists of multiple transistors (typically 2-6 depending on gate type), this translates to many billions of actual logic gates. The exact number of "gates" is difficult to specify because modern CPUs use complex transistor arrangements that don't directly correspond one-to-one with basic textb
- GeneralClass 12All
What is a full subtractor truth table
A full subtractor truth table displays all possible input combinations and their corresponding outputs for a full subtractor circuit, which performs binary subtraction of three inputs: the minuend bit (A), subtrahend bit (B), and borrow-in from the previous position (Bin), producing two outputs: the difference bit (D) and borrow-out bit (Bout). The truth table has eight rows representing all combinations of three binary inputs (000, 001, 010, 011, 100, 101, 110, 111), showing the resulting di
- GeneralClass 12All
Who is the shortest female model
Historical records identify various extremely short models, but defining "shortest female model" depends on whether you mean professional runway models, commercial models, or any modeling category. In mainstream modeling, professional models below 5'0" are exceptionally rare for high fashion, though petite and commercial modeling accommodate shorter heights. Some notably short models who achieved professional success include Devon Aoki (5'5", short for runway but successful in high fashion),