Fahad Khan

09/15/2025

Kant's Mathematical World :
Mathematics, Cognition, and Experience

09/15/2025

Bernoulli's principle is a key concept in fluid dynamics that relates pressure, speed and height. For example, for a fluid flowing horizontally Bernoulli's principle states that an increase in the speed occurs simultaneously with a decrease in pressure.

09/14/2025

🔴 Electron Shells: The Energy Levels of Atoms
🟣 Definition: Electron shells are energy levels where electrons orbit the nucleus of an atom.
🟣 Structure: Labeled as K, L, M, N… each shell holds a specific maximum number of electrons.
🟣 Capacity Rule: The formula 2n² determines how many electrons each shell can hold.
🟣 Subshells: Each shell contains subshells (s, p, d, f) with unique electron capacities.
🟣 Valence Shell: The outermost shell determines chemical reactivity and bonding.
🟣 Stability: Atoms with full valence shells (like noble gases) are generally non-reactive.
🟣 Historical Note: Concept introduced by Niels Bohr in 1913, later refined by Sommerfeld.

09/13/2025

The wave theory of everything 🌊

09/13/2025

FM in Sieve Analysis
FM = Fineness Modulus
It is an empirical index number that represents the average particle size of aggregates (fine or coarse).
It is obtained by adding the cumulative percentage retained on a specified series of standard sieves and dividing the sum by 100.
According to IS 2386 (Part I):1963, for fine aggregates, standard sieves used are: 150 µm, 300 µm, 600 µm, 1.18 mm, 2.36 mm, 4.75 mm, 10 mm.
Interpretation
Higher FM → Coarser aggregate
Reduces water demand
Improves pumpability and reduces shrinkage
But may lower workability if too coarse
Lower FM → Finer aggregate
Increases water demand for same workability
Improves cohesiveness
But may cause more shrinkage and higher cement consumption
Effect of FM on Concrete
Workability:
Coarse sand (high FM) gives harsh mixes → less workable.
Fine sand (low FM) gives higher cohesion but requires more water.
Strength:
Optimum FM (balanced grading) → denser packing of particles → higher compressive strength.
Durability:
Proper FM ensures reduced voids and permeability.
Too fine → weak and shrink-prone.
Too coarse → honeycombing risk.
Economy:
Balanced FM reduces cement consumption (since voids are minimized).
Ideal FM Values
Fine Aggregate (Sand): 2.3 – 3.1 (as per IS recommendations)
Coarse Aggregate: 5.5 – 8.0 (depending on maximum size used)
📌 For concrete mix design, sand with FM around 2.6 – 2.9 is usually preferred (neither too fine, nor too coarse).
As per Indian Standards (IS), the relevant codes for the Fineness Modulus (FM) of aggregates are mainly:
-IS 383:1970 (Specifications for Coarse and Fine Aggregates from Natural Sources for Concrete)
This code specifies that fine aggregate (sand) shall have an FM typically in the range of 2.2 to 3.2. It classifies sand into zones by grading, with limits on FM:
Fine Sand: 2.2 to 2.6
Medium Sand: 2.6 to 2.9
Coarse Sand: 2.9 to 3.2
Sand with FM less than 2.2 is considered very fine, and above 3.2 generally unsuitable for good concrete .
IS 2386 (Part 1):1963 (Methods of Test for Aggregates for Concrete - Part 1: Particle Size and Shape)
This code covers the procedure for sieve analysis that is used to determine the FM by adding cumulative % retained on specified sieves and dividing by 100. It is the standard reference for the test method .
IS codes mention that the FM is an index number used to determine the average particle size of aggregate, which influences mix proportioning, workability, strength, and durability of concrete.
Summarized IS Code Guidelines:
For Fine Aggregate (Sand), FM usually should be between 2.2 and 3.2.
Sand outside this range should be avoided or handled with adjusted concrete mix designs.
Cumulative percentages retained on standard IS sieves (from 150 µm to 10 mm for fine aggregate) are used for calculation as per IS 2386 (Part 1) procedure.
If desired, detailed sieve sizes and percentage retained for FM calculation are found in IS 2386 (Part 1) .

09/12/2025

🚀⏳ Did you know? In the realm of Einstein’s Theory of Relativity, time and space are deeply connected. The faster you move through space, the slower you move through time — a phenomenon called time dilation.
In simple words, an astronaut traveling near the speed of light would age slower than those left on Earth. On the other hand, the faster you move through time, the slower you move through space — a balance of the universe that reminds us how space and time bend together.
This isn’t science fiction — it’s proven physics. Experiments with fast-moving particles and even precise atomic clocks on airplanes confirm this strange reality. 🌌
👉 What do you think — could time travel really be possible through speed alone? Drop your thoughts below!

📖 Sources:
NASA: Time Dilation and Relativity
Scientific American: Einstein’s Time Dilation Proven

09/12/2025

✅ 𝐌𝐢𝐥𝐥𝐢𝐤𝐚𝐧’𝐬 𝐎𝐢𝐥‑𝐃𝐫𝐨𝐩 𝐄𝐱𝐩𝐞𝐫𝐢𝐦𝐞𝐧𝐭: 𝐌𝐞𝐚𝐬𝐮𝐫𝐢𝐧𝐠 𝐭𝐡𝐞 𝐂𝐡𝐚𝐫𝐠𝐞 𝐨𝐟 𝐭𝐡𝐞 𝐄𝐥𝐞𝐜𝐭𝐫𝐨𝐧

09/11/2025

This diagram shows an RC Bandpass Filter, a circuit that allows signals within a certain frequency range to pass while blocking very low and very high frequencies. It is built using resistors and capacitors, combining a high-pass and a low-pass filter in series. The lower cutoff frequency is FL and the higher cutoff frequency is FH. The center frequency is the square root of the product of FL and FH. The frequency response has a rising slope of +20 dB per decade before FL, remains almost flat in the passband, and falls with a slope of -20 dB per decade after FH. The phase response starts at +90° at low frequencies, shifts to 0° at the center frequency, and goes down to -90° at high frequencies.

09/11/2025

Projectile motion is the motion of an object thrown or projected into the air, subject to only the acceleration of gravity. The object is called a projectile, and its path is called its trajectory. The motion of falling objects, as covered in Problem-Solving Basics for One-Dimensional Kinematics, is a simple one-dimensional type of projectile motion in which there is no horizontal movement. In this section, we consider two-dimensional projectile motion, such as that of a football or other object for which air resistance is negligible.

09/10/2025

A transistor is a semiconductor device used to amplify or switch electrical signals and power. It is one of the basic building blocks of modern electronics. It is composed of semiconductor material, usually with at least three terminals for connection to an electronic circuit.

09/08/2025

09/08/2025

Magnetic Effect of electric current ⚡️