MEDIUM
9th CBSE
IMPORTANT
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Assertion: The loudness of sound is measured in decibel.
Reason: If sound waves have a large amplitude then the sound will be loud.

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Important Questions on Sound

MEDIUM
9th CBSE
IMPORTANT
Assertion: Ultrasonic sound is used in industry for detecting flaws (cracks etc) in metal blocks without damaging them.
Reason: An internal crack (or hole) does not allow ultrasound to pass through it.
MEDIUM
9th CBSE
IMPORTANT
What is the nature of the ocean waves in deep water?
MEDIUM
9th CBSE
IMPORTANT
What will increase, if we change feeble sound to loud sound?
MEDIUM
9th CBSE
IMPORTANT
Which physical quantity remains unchanged after reflection of sound wave?
EASY
9th CBSE
IMPORTANT
Give the principle involved in megaphone.
EASY
9th CBSE
IMPORTANT
The window panes of houses sometimes crack when bomb explodes even at a large distance. Why?
MEDIUM
9th CBSE
IMPORTANT
How do submarines know the depth of a sea?
EASY
9th CBSE
IMPORTANT
What is compression and rarefaction in longitudinal wave? Explain.