How can we build a chatting app like whatsapp that works on phone text messaging

To build a chat app like WhatsApp that runs on phone text messaging, you need to use an SMS Gateway API, set up a backend server, and create a mobile user interface. [1, 2]

Core Architecture & Tools

SMS Gateway API: Use services like Twilio or Vonage to send and receive real phone text messages (SMS) programmatically.
Backend Server: Build a server using Node.js or Erlang to process incoming and outgoing text logs.
Database: Store user phone numbers, message history, and profile data using databases like PostgreSQL, Firebase Firestore, or MongoDB.
Mobile Frontend: Develop cross-platform mobile screens using Flutter or React Native so the app works on both Android and iOS. [1, 2, 3, 4, 5]

Development Steps

User Verification: Implement phone number login by sending a random verification code via SMS.
Sync Contacts: Request permission to read the phone’s address book and match numbers registered in your database.
Message Routing: Connect your mobile app to the backend so that when a user hits send, the app triggers an API request to dispatch an SMS or sync through your server data pipeline

Moving electric charge

 An electric charge moving with a uniform velocity produces both an electric field and a magnetic field, but it does not radiate energy as electromagnetic waves. The constant motion of the charge effectively acts as an electric current, which generates the magnetic field in its surrounding space. 

When an electric charge accelerates, it produces an electric field, a magnetic field, and radiates energy in the form of electromagnetic waves (such as light, X-rays, or radio waves). 

Here is exactly what happens when a charge speeds up, slows down, or changes direction:

Key Effects of an Accelerating Charge

• 🔊 Electromagnetic Radiation: The acceleration creates a disturbance in the surrounding electric and magnetic fields. This disturbance detaches from the charge and travels through space as an electromagnetic wave, carrying energy away. 
• ⚡ Changing Electric Field: The electric field lines bend and kink because the change in velocity takes time to propagate through space. 
• 🧲 Changing Magnetic Field: A changing electric field generates a changing magnetic field, sustaining the self-propagating electromagnetic wave.

Electrolysis

 

Key Components of Electrolysis

Electrolyte: A liquid, molten ionic compound, or aqueous solution that contains free-moving ions to carry the electric current.
Cathode: The negative electrode where positive ions (cations) gain electrons in a reduction reaction.
Anode: The positive electrode where negative ions (anions) lose electrons in an oxidation reaction.


How the Process Works
Ion Movement: Opposites attract, so positive ions move to the cathode and negative ions move to the anode.
Electron Transfer: The power source forces electrons into the cathode and pulls them away from the anode.
Non-Spontaneous Reaction: Electricity drives a chemical change that would not happen on its own.

47000 has 2 significant figures while 47000.000 has 8 significant figures...why? when both are the same value.

 

Significant figures refer to the digits in a measured or calculated value that carry meaningful information about its precision. 

They include all digits known with certainty based on the measuring tool, plus the very first estimated (uncertain) digit i.e. rounded digit. 

Understanding Certainty and Estimation

When measuring, for instance, a table length with a standard centimeter ruler, you might observe that it lands between 15.2 cm and 15.3 cm.

You know for sure it is 15 cm.

You visually estimate the last decimal place, guessing it falls about halfway, reporting 15.25 cm.

In this measurement, 1, 5, and 2 are completely certain, while the 5 is an estimate. All four are your significant figures. 

what happens to the hydrogen gas that is bubbled in SHE

 

electronegativity vs reduction potential

 

Periodic trends in electronegativity