OnlineCBT
Physics · PYQ NEET UG 2018
हिन्दीA tuning fork is used to produce resonance in a glass tube. The length of the air column in this tube can be adjusted by a variable piston. At room temperature of \( 27 ^\circ\text{C} \) two successive resonances are produced at \( 20 \text{ cm} \) and \( 73 \text{ cm} \) of column length. If the frequency of the tuning fork is \( 320 \text{ Hz} \), the velocity of sound in air at \( 27 ^\circ\text{C} \) is
Correct answer · Option 2
\( 339 \text{ m/s} \)
Explanation
Half wavelength \( \frac{\lambda}{2} = l_2 - l_1 = 73 \text{ cm} - 20 \text{ cm} = 53 \text{ cm} = 0.53 \text{ m} \). So \( \lambda = 1.06 \text{ m} \). Velocity \( v = f \lambda = 320 \times 1.06 = 339.2 \text{ m/s} \approx 339 \text{ m/s} \).
