NTA Abhyas JEE Main2020PhysicsWaves and SoundPractice
A pipe of length 1 . 5 m closed at one end is filled with gas and resonates in its fundamental mode with a tuning fork. Another open organ pipe of same dimensions filled with air resonates in its fundamental mode with the same tuning fork. If this experiment is performed at 30 ° C , then the speed of sound at 0 ° C in the same gas is (Speed of sound in air is 360 m / s )
Options
- A580 m / s
- B683   m / s
- C880   m / s
- D743 m / s
Correct answer
B. 683   m / s
Step-by-step solution
For open pipe f = v 2 ℓ = 360 2 × 15 = 120 Hz For the closed at one end pipe, let the velocity of sound in gas at 30 ° C be v ' f ' = v ' 4 ℓ = v ' 4 × 1 . 5 = v ' 6 Since same tuning fork is used frequency will be same and thus, f ' = f ⇒ v ' = 720 m / s Also v ∝ T ⇒ v = 720 × 273 303 = 683 m / s .