Answer: The length of the closed tube is 1.05 m
Step-by-step explanation:
Wave speed is defined as the product of its wavelength and frequency.
Mathematically,

where,
= length of the closed tube = ?
= frequency of the tuning fork = 320 Hz =

Speed of the sound wave = 335 m/s
Putting values in above equation, we get:

Hence, the length of the closed tube is 1.05 m