Answer:
The number of bright-dark fringe is 42
Solution:
As per the question:
Wavelength of light, 
Length of the glass cell, x = 3.73 cm = 0.0373 m
Refractive index, 
Now,
To calculate the bright-dark fringe shifts, we use the formula given below:

Now, substituting the appropriate values in the above formula:

≈ 42
Answer:
Number of rollers required to complete the compaction are 2
Explanation:
The solution is given in the attachments.
Answer:
2.379m
Explanation:
The width = 23m
The depth = 3m
The radius is denoted as R
The wetted area is = A
The perimeter perimeter = P
Hydraulic radius
R = A/P
The area of a rectangular channel
= Width multiplied by Depth
A = 23x3
A = 69m²
Perimeter = (2x3)+23
P = 6+23
P= 29
Hydraulic radius R = 69/29
= 2.379m
This answers the question
Thank you!