The answer is choice C
Explanation:
As during construction ,the site is cleared for all debris before laying out the foundation. Even the sewer lines are dug out .
So it will be useful for the construction crews to connect the pipes to the sewer lines before the foundation is poured.
But usually the steps take in construction activity is:- first the site is cleared for the foundation to be poured and once the foundation wall is set , then all utilities , including plumbing and electrical activities are done.,
After this process is over, the city inspector comes to check whether the foundation has been laid down as per the code of construction.
Only after that the rest of the construction activity follows through.
Answer:
Frequency = 
Wavenumber = 
Energy = 
Energy = 1.4579 eV
Energy = 
Explanation:
As we are given the wavelength = 850 nm
conversion used : 
So, wavelength is 
The relation between frequency and wavelength is shown below as:

Where, c is the speed of light having value = 
So, Frequency is:


Wavenumber is the reciprocal of wavelength.
So,


Also,

where, h is Plank's constant having value as 
So,


Also,

So,


Also,

So,


Answer:
Vc2= V(l+e) ^2/4
Vg2= V(l-e^2)/4
Explanation:
Conservation momentum, when ball A strikes Ball B
Where,
M= Mass
V= Velocity
Ma(VA)1+ Mg(Vg)2= Ma(Va)2+ Ma(Vg)2
MV + 0= MVg2
Coefficient of restitution =
e= (Vg)2- (Va)2/(Va)1- (Vg)1
e= (Vg)2- (Va)2/ V-0
Solving equation 1 and 2 yield
(Va)2= V(l-e) /2
(Vg)2= V(l+e)/2
Conservative momentum when ball b strikes c
Mg(Vg)2+Mc(Vc)1 = Mg(Vg)3+Mc(Vc)2
=> M[V(l+e) /2] + 0 = M(Vg)3 + M(Vc) 2
Coefficient of Restitution,
e= (Vc)2 - (Vg)2/(Vg)2- (Vc)1
=> e= (Vc)2 - (Vg)2/V(l+e) /2
Solving equation 3 and 4,
Vc2= V(l+e) ^2/4
Vg2= V(l-e^2)/4