Explanation

• A Modem (Modulator-Demodulator) converts digital signals into analog signals and vice versa.
• It is used to connect computers to the internet via telephone lines or other networks.

Additional information:

• Switch – connects multiple devices in a network
• Hub – basic network connector
• Repeater – boosts signal strength
• Router – directs internet traffic

Last verified on 19-04-2026

Explanation

• Classified documents contain sensitive/confidential information that is restricted to authorized personnel only.
• They are protected to prevent unauthorized access or disclosure.
• Such documents may relate to national security, defense, intelligence, or confidential government matters.
• Only officials with proper security clearance can access them.

Last verified on 08-07-2026

Explanation

• Blockchain technology is primarily associated with cryptocurrency and secure digital transactions.
• It is a decentralized digital ledger that records transactions securely and transparently.
• Blockchain reduces the need for intermediaries and makes data difficult to alter.
• It is widely used in cryptocurrencies, finance, supply chains, and digital identity systems.
• The technology became globally popular with the launch of Bitcoin in 2009.

Last verified on 08-07-2026

Explanation

• A Digital Signature is used for cryptographic authentication of identity and to verify that a document has not been altered.
• It provides authentication, integrity, and non-repudiation for electronic documents.
• Digital signatures are created using public key cryptography (PKI).
• They are widely used in e-governance, banking, legal documents, and online transactions.

Last verified on 08-07-2026

Explanation

• JPEG is a lossy image compression format that reduces file size by permanently removing some image data.
• It is widely used for digital photographs and web images.
• JPEG provides a good balance between image quality and file size.
• Repeated saving of a JPEG image may reduce its quality further.

Last verified on 08-07-2026