Questions

After the defeat of china by Japan in a war over Korea in 1894,France, Russia, Britain and Germany gave loan to china to help it to the payment of 150 million dollors demanded by japan. These western countries the divided china into spheres of influence, which meant that each country had certain regions of china reserved exclusively for its purposes.

          The united states feared that china would be completely parcelled out in exclusive 'spheres of influence' and that its trade with china would be shut off. The USA, therefore, suggested the policy known as the "Open Door". This policy is also described as "Mee too Policy".

          The division of China into "spheres of influence' has often been described as the "cutting of the Chinese melon".

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.