Question

An instrument based on the principle of echo is

• A. sonar
• B. metre scale
• C. radar
• D. barometer

Answer 1

Answer: (A), (C)

radar

Explanation for correct answer:

(A) Sonar:

1. The word 'sonar' refers to Sound Navigation and Ranging.
2. It is an instrument used to find the depth of a sea or investigate the under water objects like submarines and ship wrecks.
3. It is based on the principle of echo.

(C) Radar

1. The basic principle behind radar is simple - extremely short bursts of radio energy are transmitted, reflected off a target and then returned as an echo.
2. It is based on the principle of echo.

Explanation for incorrect answer:

(B) Meter scale:

1. It is used to measure length.

(D) Barometer

1. It works on principle of balancing the atmospheric pressure with the volume of mercury present in the device.

Hence, correct answer is (A) and (C).