Answer:
330.24 Hz
Explanation:
Given: 
Frequency, f = 320 Hz
L1 = 25.8 cm
L2 = 78.4 cm 
L3 = 131.1 cm
 Let the wavelength be λ
Then, L1 which is the length of the column of air is  λ/4. 
λ/4 = 25.8 cm 
λ = 25.8 × 4 = 103.2 cm = 1.032 m 
Then, speed of sound in air is:
v = λ f
⇒ v = 1.032 × 320 Hz
⇒ v = 330.24 m/s
 
        
             
        
        
        
atoms of lithium, sodium,
and potassium almost never found alone in nature because t<span>hey have only one electron in their outer most
shell which makes them very reactive and they react with other atoms thats why.
I hope this can help you</span>
 
        
             
        
        
        
C an inclined plate
youre welcome