GK: Class 12 General Q&A · Page 22
3,658 free answers on GK (General) for Class 12 students, across CBSE, ICSE and State boards.
Question & Answer
Questions
- GeneralClass 12All
What shapes have CSA
Shapes that have Curved Surface Area (CSA) are three-dimensional objects with curved surfaces, as opposed to polyhedra which have only flat faces. Common shapes with CSA include cylinders (CSA = 2πrh), cones (CSA = πrl where l is slant height), spheres (CSA = 4πr² = TSA since spheres are entirely curved), hemispheres (CSA = 2πr²), frustums of cones, spherical caps, ellipsoids, toruses (donut shapes), and any other 3D shape featuring curved surfaces. If a shape has any ro
- GeneralClass 12All
Is 5ft short for a girl in India
At 5 feet (152 cm), a woman in India is slightly below the average female height but not unusually short. The average height for Indian women varies across regions and demographics but generally ranges from approximately 152-155 cm (5'0"-5'1"), making 5 feet right around the average. Regional, genetic, nutritional, and socioeconomic factors create considerable height variation within India, so 5 feet might be perfectly average in some areas while slightly below average in others, particularly
- GeneralClass 12All
How tall are 14 year old models
Teen models who are 14 years old and working professionally in fashion modeling typically range from about 5'7" to 5'10" (170-178 cm), though this varies based on modeling category and individual growth patterns. At 14, teenagers are still growing, and modeling agencies often scout young teens based on projected adult height and current body proportions rather than just current measurements. Teen models usually work in junior, teen, or young adult fashion categories rather than adult runway o
- GeneralClass 12All
What is the SA/V ratio
The surface area to volume ratio (SA/V or SA:V ratio) compares an object's external surface area to its internal volume, typically expressed as a number with units of inverse length (like cm⁻¹ or m⁻¹). This ratio is calculated by dividing surface area by volume, and it reveals how much surface exists relative to the amount of material or space enclosed. For a sphere, SA/V = 4πr²/(4/3πr³) = 3/r, showing that smaller spheres have higher SA/V ratios while larger spheres
- GeneralClass 12All
What is a 3D circle called
A 3D circle is called a sphere, which is the three-dimensional equivalent of a circle extended into space. While a circle is a flat, two-dimensional shape where all points are equidistant from a center point on a plane, a sphere is a perfectly round three-dimensional object where all points on its surface are equidistant from a center point in space. The sphere represents the set of all points at a fixed distance (the radius) from its center in three-dimensional space. The terminology
- GeneralClass 12All
What is a 4-dimensional sphere called
A four-dimensional sphere is called a hypersphere or 4-sphere (sometimes written as S³ in mathematical topology). While we can't visualize a true 4D sphere since we exist in three spatial dimensions, mathematically it's defined as the set of all points at a fixed distance from a center point in four-dimensional space. The 3D sphere we're familiar with is actually the surface (or boundary) of a 4D ball, just as a 2D circle is the boundary of a 3D ball. Understanding 4D spheres req
- GeneralClass 12All
Is a ball a 2D or 3D shape
A ball is definitively a three-dimensional (3D) shape because it occupies space in three dimensions—length, width, and height—and possesses volume. When we refer to a ball in everyday language (like a basketball, tennis ball, or soccer ball), we're describing a physical, tangible object that exists in three-dimensional space, which you can hold, measure the volume of, and observe from multiple angles. Mathematically, a ball is the solid region enclosed by a sphere, including all i
- GeneralClass 12All
What is a 3D half sphere called
A 3D half sphere is called a hemisphere, derived from the Greek words "hemi" (half) and "sphere." A hemisphere is created by cutting a complete sphere along any plane that passes through its center, resulting in two identical halves, each with a flat circular base and a curved dome-like surface. The equator on Earth, for example, divides the planet into the Northern and Southern Hemispheres. Hemispheres have unique geometric properties with specific formulas distinct from full spheres
- GeneralClass 12All
What is TSA vs CSA vs LSA
Total Surface Area (TSA), Curved Surface Area (CSA), and Lateral Surface Area (LSA) are three ways of measuring surfaces on three-dimensional shapes, with TSA including all surfaces (curved and flat), while CSA and LSA both refer to only the curved or side surfaces excluding bases—CSA and LSA are effectively synonymous terms used interchangeably depending on regional or contextual preferences. TSA provides the complete measurement of everything you see from outside the shape, while CSA/
- GeneralClass 12All
Whose formula is l × b × h
The formula l × b × h (length × breadth × height) for calculating the volume of a rectangular prism is not attributed to any single mathematician—it's a fundamental geometric principle that has been understood since ancient times across multiple civilizations. This formula represents basic volumetric calculation derived from the concept that volume equals the area of a shape's base multiplied by its height, and for rectangles, the base area is length times breadt
- GeneralClass 12All
How to measure photo frame size
To measure a photo frame size, measure the dimensions of the frame opening (where the photo or artwork sits), not the outer edge dimensions of the frame itself, since frame size conventionally refers to the picture it holds, not the frame's total outer measurements. Use a ruler or tape measure to measure the width (horizontal) and height (vertical) of the opening in inches or centimeters, recording as width × height (for example, 8×10 inches). Understanding frame measureme
- GeneralClass 12All
What is Half Adder in computer science
A half adder is a fundamental digital logic circuit in computer science that adds two single binary digits (bits) and produces two outputs: a sum bit and a carry bit. It's called a "half" adder because it handles only two inputs without accommodating a carry-in from a previous bit position, making it the simplest form of binary adder. The half adder implements the basic addition rules: 0+0=0 (sum=0, carry=0), 0+1=1 (sum=1, carry=0), 1+0=1 (sum=1, carry=0), and 1+1=10 in binary (sum=0, carry=1
- GeneralClass 12All
How many sqft is a 12x10 room
A 12×10 room contains 120 square feet of floor space, calculated by multiplying the length (12 feet) by the width (10 feet). This calculation gives you the total area of the floor surface, which is essential for determining quantities of flooring materials, carpeting, tile, paint coverage for floor treatments, furniture placement planning, and understanding spatial capacity. Understanding room square footage is fundamental for home improvement, renovation planning, and space uti
- GeneralClass 12All
What size is a 10'12" in girls
Girls' clothing size 10-12 (sometimes written as 10/12 or 10-12) typically fits children approximately 10-12 years old, though sizing by age is just a rough guideline since children develop at different rates. This size range generally accommodates chest measurements of 29-30 inches, waist measurements of 24-25 inches, and hip measurements of 31-32 inches, with heights roughly 54-59 inches (4'6" to 4'11"). However, these measurements vary significantly between brands, and it's crucial to chec
- GeneralClass 12All
How can I check my height
To accurately check your height, stand barefoot with your back against a flat wall, feet together, and heels touching the wall, keeping your body straight with shoulders relaxed and head level (not tilted up or down). Have someone place a flat object like a book or ruler on top of your head, perfectly horizontal and pressed firmly against the wall, then mark where the bottom edge meets the wall. Step away and measure from the floor to the mark using a tape measure or meter stick for your heig
- GeneralClass 12All
Can a 5'3" girl be a model
Yes, a 5'3" girl can absolutely be a model, though the specific modeling opportunities available depend on the type of modeling rather than just height alone. While traditional high fashion runway and editorial modeling typically requires taller heights (usually 5'9" and above for women), numerous other modeling categories actively seek models in the 5'3" range: commercial/print modeling, petite modeling, parts modeling (hands, feet, face), fitness modeling, lifestyle modeling, plus-size mode
- GeneralClass 12All
What is a binary adder
A binary adder is a digital electronic circuit that performs addition of binary numbers (numbers expressed in base-2 using only digits 0 and 1), forming the fundamental arithmetic component of computer processors and calculators. These circuits combine binary digits using logic gates to produce sum and carry outputs, implementing the same addition process humans use with decimal numbers but adapted for binary arithmetic. Binary adders range from simple half adders and full adders that add sin
- GeneralClass 12All
What is a full adder truth table
A full adder truth table displays all possible input combinations and their corresponding outputs for a full adder circuit, which adds three binary inputs (two data bits plus a carry-in bit) and produces two outputs (a sum bit and a carry-out bit). The truth table has eight rows representing all possible combinations of the three inputs (000, 001, 010, 011, 100, 101, 110, 111), with columns showing the resulting sum and carry-out for each combination. The full adder truth table is: wh
- GeneralClass 12All
Is sum mean plus
The word "sum" specifically means the result of addition—the total obtained by adding two or more numbers together. While "plus" is the operation or symbol (+) that indicates addition should be performed, "sum" is the answer produced by that operation. So they're related but not identical: "plus" describes the action or process of adding, while "sum" describes the outcome of that addition. Understanding this distinction helps clarify mathematical language. When you see "5 plus 3
- GeneralClass 12All
What is ripple carry adder
A ripple carry adder is a digital circuit that performs binary addition of multi-bit numbers by chaining together multiple full adder units, where the carry output from each bit position "ripples" sequentially to the next higher bit position. This design is called "ripple" because the carry bit must propagate through each stage one at a time, like a wave rippling across the circuit, before the final sum is complete. While conceptually straightforward and simple to implement, this sequential c