EASY
9th CBSE
IMPORTANT
Earn 100

What is an echo? How is echo formed?

Important Questions on Sound

EASY
9th CBSE
IMPORTANT
Science for Ninth Class Part 1 Physics>Chapter 5 - Sound>Long Answer Type Questions>Q 63
What is the minimum distance in the air required from a sound-reflecting surface to hear an echo (at 20 °C)?
EASY
9th CBSE
IMPORTANT
Science for Ninth Class Part 1 Physics>Chapter 5 - Sound>Long Answer Type Questions>Q 63
A man standing 825 meters away from a cliff (steep rock) fires a gun. After how long will he hear its echo? The Speed of sound in air is 330 ms.
MEDIUM
9th CBSE
IMPORTANT
Science for Ninth Class Part 1 Physics>Chapter 5 - Sound>Long Answer Type Questions>Q 64
What is ultrasound? What is the difference between ordinary sound and ultrasound?
MEDIUM
9th CBSE
IMPORTANT
Science for Ninth Class Part 1 Physics>Chapter 5 - Sound>Long Answer Type Questions>Q 64
Write any three applications (or uses) of ultrasound.
MEDIUM
9th CBSE
IMPORTANT
Science for Ninth Class Part 1 Physics>Chapter 5 - Sound>Long Answer Type Questions>Q 65
What are infrasonic waves? Name two animals which produce infrasonic waves.
MEDIUM
9th CBSE
IMPORTANT
Science for Ninth Class Part 1 Physics>Chapter 5 - Sound>Long Answer Type Questions>Q 65
What are ultrasonic waves? Name two animals which can produce ultrasonic waves.
MEDIUM
9th CBSE
IMPORTANT
Science for Ninth Class Part 1 Physics>Chapter 5 - Sound>Long Answer Type Questions>Q 65
The audible range of frequencies of an average human ear is from 20 Hz to 20 kHz. Calculate the corresponding wavelengths. (Speed of sound in air is 344 m s-1)
MEDIUM
9th CBSE
IMPORTANT
Science for Ninth Class Part 1 Physics>Chapter 5 - Sound>Long Answer Type Questions>Q 66
Define the term echolocation.