Question

RADAR is used for:

• A. Locating submerged submarines
• B. Receiving a signal in a radio receiver
• C. Locating geostationary satellites
• D. Detecting and locating objects such as aeroplanes

Hint:

Radar works by sending out radio waves and picking up the echo reflected back from an object.

Answer 1

The Correct Option is D

Step 1: Expand the term.
RADAR stands for Radio Detection And Ranging, a system built around sending and receiving radio waves.
Step 2: Follow the working principle.
A radar transmitter sends out short pulses of radio waves. When these waves strike an object such as an aeroplane, part of the energy reflects back towards the radar station as an echo.
Step 3: Use the echo.
The radar receiver picks up this echo, and by timing how long it took to return, along with the direction it came from, the system calculates the distance and position of the object.
Step 4: Rule out the other options.
Locating submerged submarines is done using sonar, which uses sound waves in water, not radio waves. Receiving a normal radio signal and locating fixed geostationary satellites are different tasks unrelated to the echo based detection radar performs.
Final Answer: D) Detecting and locating objects such as aeroplanes.