Electrons drift in a conductor from lower to higher potential, does this mean that all free electrons are moving in the same direction?

 

find value of a for which f(x) = x^2 -2ax + b f(x) is an increasing function for x>0

 

Determinant of a skew symmetric matrix

 

If A is a square matrix of order 3 such that det(A)=9, then det(9A^-1) is?

 

If A is a 3x3 matrix , B is a 3x1 matric and C is a 1x3 matric then only AB and BC are defined?

 The statement is false because, in addition to AB and BC, the matrix products AC and  CB are also perfectly well-defined. 

Conclusion

Apart from AB and BC, the products CB and CA are also defined. 

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.