Explanation

In the Format Cells box, click the Number tab. In the Category list, click Date, and then choose a date format you want in Type.

You can adjust this format in the last step below.

Go back to the Category list, and choose Custom.

Explanation

A unique constraint is a rule that forbids duplicate values in one or more columns within a table. Unique and primary keys are the supported unique constraints.

Explanation

WhatsApp allows users to send text, voice messages and video messages, make voice and video calls, and share images, documents, user locations, and other content. 

Initial release date: November 2009

Original authors: Brian Acton, Jan Koum

Yahoo was founded by Jerry Yang and David Filo in January 1994 and was incorporated on March 2, 1995.

Founded: January 1994

Headquarters: Sunnyvale, California, United States

Gmail is a free email service provided by Google.

Date launched: April 1, 2004

Created by: Paul Buchheit

Explanation

Cathode rays are produced when there is a potential difference (voltage) applied across the electrodes. 

Explanation

There are three logical operators: and , or , and not .

Explanation

Input/Output has Direct Access to main memory.

Explanation

The fourth generation of computers is marked by the use of Very Large Scale Integrated (VLSI) circuits.

VLSI starts in 1970

Explanation

Technology is the application of knowledge for achieving practical goals in a reproducible way.

Explanation

ULSI stands for Ultra Large Scale Integration.

ULSI is the process of integrating or embedding millions of transistors on a single silicon semiconductor microchip.

ULSI technology was conceived during the late 1980s.

Explanation

EEPROM Stand for Electrically erasable programmable read-only memory.

EEPROM is a special type of PROM that can be erased by exposing it to an electrical charge.

EEPROM is similar to Flash Memory