Answer:
The distance between the two slits is 40.11 μm.
Explanation:
Given that,
Frequency 
Distance of the screen l = 88.0 cm
Position of the third order y =3.10 cm
We need to calculate the wavelength
Using formula of wavelength
where, c = speed of light
f = frequency
Put the value into the formula
We need to calculate the distance between the two slits
Where, m = number of fringe
d = distance between the two slits
Here, 
Put the value into the formula
Hence, The distance between the two slits is 40.11 μm.
Answer: B. Concrete
Explanation:
Let N = reacting force pressing the bodies in context together (units in Newtons),
The question stated that the force pressing the two mounted/stacked objects together is equal to the weight of the object on top.
We need to start by finding the weight of the piece of wood.
friction is given by
f = μN
The value of f is 22.5,
and from the chart reference the coefficient of friction between wood and stone, μ is 0.30.
22.5 = 75. 0.30
Putting the values into the equation: 22.5 = 0.30N.
Divide both sides by 0.30 to find the value of N:
N= 22.5/0.3 = 75
Now that the piece of wood will be placed on another surface, its weight of 75 Newton is the force pressing the two bodies together.
To determine the new surface, you should find the new coefficient of friction by using the new value of the force of friction given 46.5:
46.5 = µ(75).
Divide both sides by 75 to isolate μ.
The refer chart also indicates that the coefficient of friction equals 0.62 between wood and concrete, so the new surface corresponding to 0.62 is the concrete, which is (B).
Your answer is cod!!!
Hope this helped!!
~xox Melis
I Think The answer is d I hope it helps My friend Message Me if I’m wrong and I’ll change My answer and fix it for you
