Science And Technology

South Korea was the first country to launch the world’s first 5G mobile network service in 2019, setting a benchmark for other countries.

Step 1: Understand the term light year.
A light year is defined as the distance travelled by light in vacuum in one year.
Step 2: Clarify common confusion.
Although the word "year" refers to time, a light year measures how far light travels, not how long it takes.
Step 3: Conclusion.
Hence, a light year is a unit of distance.

Step 1: Understand PDF.
PDF is a file format developed to present documents consistently across different devices and platforms.
Step 2: Analyze the options.
Portable Document Format is the correct and official expansion of PDF.
Other options are incorrect or unofficial terms.
Step 3: Conclusion.
Hence, PDF stands for Portable Document Format.

Step 1: Understand the term ``Red Planet''.
The planet Mars appears red in the night sky due to the presence of iron oxide (rust) on its surface.
Step 2: Analyze the options.
Venus is known for its thick atmosphere.
Jupiter is the largest planet.
Saturn is famous for its rings.
Mars is called the Red Planet because of its reddish appearance.
Step 3: Conclusion.
Therefore, Mars is known as the Red Planet.

Step 1: Understand ChatGPT.
ChatGPT is an artificial intelligence language model designed for natural language conversations.
Step 2: Identify the developer.
ChatGPT was developed and released by OpenAI, an AI research organization.
Step 3: Analyze other options.
Google and Meta develop AI tools but did not create ChatGPT.
Microsoft partners with OpenAI but is not the original developer.
Step 4: Conclusion.
Hence, ChatGPT was developed by OpenAI.

Step 1: Understand the rebranding.
Twitter underwent a rebranding after being acquired by Elon Musk.
Step 2: Identify the new name.
The platform was officially renamed to ``X''.
Step 3: Analyze other options.
Threads is a different social media platform by Meta.
Mastodon is a decentralized social network.
Telegram is a messaging application.
Step 4: Conclusion.
Therefore, the social media platform formerly known as Twitter is now called X.

Step 1: Understand the origin of the WWW.
The World Wide Web was invented to allow information sharing over the Internet using hyperlinks and web pages.
Step 2: Identify the inventor.
Tim Berners-Lee developed the World Wide Web in 1989 while working at CERN.
Step 3: Analyze other options.
Bill Gates is associated with Microsoft.
Steve Jobs co-founded Apple.
Vint Cerf is known as a father of the Internet, not the Web.
Step 4: Conclusion.
Therefore, Tim Berners-Lee is known as the father of the World Wide Web.

Step 1: Understand ISRO.
ISRO stands for Indian Space Research Organisation, which is India's national space agency.
Step 2: Identify the headquarters.
The headquarters of ISRO is located in Bengaluru (Karnataka).
Step 3: Conclusion.
Therefore, the correct answer is Bengaluru.

Step 1: Define electric power.
Electric power is the rate at which electrical energy is consumed or converted.
Step 2: Recall SI units.
The SI unit of power is the watt (W).
Step 3: Compare with other units.
Joule is the unit of energy.
Volt is the unit of electric potential difference.
Ampere is the unit of electric current.
Step 4: Conclusion.
Therefore, the SI unit of electric power is Watt.

Step 1: Identify common salt.
Common salt is chemically known as sodium chloride.
Step 2: Understand the chemical composition.
It is made up of sodium (Na) and chlorine (Cl).
Step 3: Analyze the options.
H O is water.
KCl is potassium chloride.
CO is carbon dioxide.
Step 4: Conclusion.
Hence, the chemical formula of common salt is NaCl.

Step 1: Understand the invention.
The telephone is a device used for transmitting sound over long distances.
Step 2: Identify the inventor.
Alexander Graham Bell is credited with inventing the first practical telephone in 1876.
Step 3: Analyze other options.
Thomas Edison worked on electrical inventions but did not invent the telephone.
Nikola Tesla contributed to electrical engineering.
Albert Einstein was a physicist, not an inventor of communication devices.
Step 4: Conclusion.
Therefore, the telephone was invented by Alexander Graham Bell.