Answer B is the correct pair.
Answer:
The intensity at a spot 71 m away is 
Explanation:
Given:
Initial intensity,
at a distance, 
Required:
New intensity,
at a distance, 
Using the inverse square law,
I ∝ 
⇒

×

Thus, the intensity at a spot that is 71 m away is 
given that initial velocity is

deceleration is given as

now we have to find the distance covered in 16 s



so it will cover 137.6 m distance
part b)
in order to find the final speed



so its speed will be 6.2 m/s
Answer
given,
Length of pipe, L = 2.65 m
speed of sound, v = 343 m/s
Pipe is open end Pipe
a) Lowest frequency
condition, for open end pipe


For lowest frequency

n = 1

f₁ = 64.72 Hz
b) For second frequency in bugle
n = 2

f₂ = 129.43 Hz
for n = 3

f₃ = 194.16 Hz