2. Radar is the most necessary instrument of modern age. Radar is of two types. 1-Continous high frequency radio wave. 2-Vibrational radio wave. In the first case Radar transmits high frequency radio wave in all direction. The second one transmits Vibration radio wave.

4. (i)- For the movement of aircraft and ship, its use is most valuable. It also decides the distance, situation and direction of the above. (ii)- The major function of radar is to locate the position of enemies’ aircrafts and missiles at the time of war.

5. continue (iii)- The invisible object in space reflects this wave back. Radar receives these waves and tell us the direction and the time taken by them to travel the distance from radar to the objects and back. Knowing the velocity of these wave (3*1010cm/s), we can find the distance and thus the velocity of the object.