Questions

The paste applied to the side of a match box is a mixture of phosphorus trisulphide, glass powder (or sand) to cause friction and glue (binding material)

RADAR - RAdio Detection And Ranging.

A radar system consists of a transmitter producing electromagnetic waves in the radio or microwaves domain, a transmitting antenna, a receiving antenna (often the same antenna is used for transmitting and receiving) and a receiver and processor to determine properties of the objects. 

Radar is an object-detection system that uses radio waves to determine the range, angle, or velocity of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain.

Radio waves from the transmitter reflect off the object and return to the receiver, giving information about the object's location and speed.

Internet Protocol version 4 (IPv4) which defined an IP address as a 32-bit value

IPv4 is in contrast to IPv6, which defined an IP address as a 128 bits value.

The default return value from a function is int. In other words, unless explicitly specified the default return value by compiler would be integer value from function.

Key elements in the procurement management plan are enumerated in this PMBOK section. [12.1.3.1]