CE 111:
ENVIRONMENTAL ENGINEERING
SAMPLE FINAL EXAM
Page 1
(from Fall 2002)
NAME
GROUND RULES: This exam consists of 6 sets of questions/problems.
You are permitted
three sheets of notes, but otherwise the exam is closedbook/closednote.
Do your work on the
paper provided.
Be sure your name is on every page you submit, and that the problem number
and your answer are clearly marked.
The total score possible is 60 points, and the time allowed
is 180 minutes.
Use the time to maximize your score.
If you need a conversion factor, or you
are not clear about what a problem requires, ask.
[
Hint:
The final two pages of the exam
contain many equations, conversion factors, etc.
All are true.
Some may be useful.
(
Note
:
These pages reproduced the inside covers, both front and back, from the text.
They are not
reproduced in this sample.)
]
GOOD LUCK!
SCORE
#1 (14 possible) _____________
#2 (12 possible) ____________
#3 (12 possible) ____________
#4 (8 possible)
____________
#5 (8 possible) ____________
#6 (6 possible) ____________
EXAM TOTAL (out of 60)
Note: The overall average score for the 42 students who took this exam was 42.7 (71%).
For
the 31 undergraduate students the average score was 40.0 (67%).
COURSE SCORE (%)
COURSE GRADE
Your “course score” is the weighted average of the percentage of possible points you achieved
during the semester.
The relative weights and your scores are indicated below:
element
weight (%)
your score (%)
assignments
25
_______
midterms
30
_______
final exam
45
_______
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View Full DocumentCE 111:
ENVIRONMENTAL ENGINEERING
SAMPLE FINAL EXAM
Page 2
(from Fall 2002)
1. WARMUP EXERCISES (14 points; 2 each)
(a) Fick’s law in one dimension is J =  D dC/dx.
Define each of the variables in the equation
(J, D, C, and x) and give the associated dimensions.
(b) Darcy’s law in one dimension can be written U = K dh/dl.
Define each of the variables in
the equation (U, K, h, and l) and give the associated dimensions.
(c) Particleladen water enters a gently stirred CMFR.
Within the CMFR, particles that settle
to the bottom remain there.
The CMFR volume is V and the water flow rate through it is Q.
The CMFR is in the shape of a rightcircular cylinder with its axis oriented vertically, such
that V = AH where H is the height of water and A is the crosssectional area.
All particles
have the same settling velocity v
t
.
For a long period prior to the time of interest, the inlet
particle concentration was C
1
, and the system was at steady state. Then, at t = 0, the inlet
particle concentration is suddenly increased to C
2
.
What is the characteristic time required
for the new steadystate condition to be established?
(d) Wastewater is discharged at a point at the edge of a river.
As the wastewater is transported
by advection downstream, it mixes across the river by turbulent diffusion.
The river has
width W, mean water velocity U, and turbulent diffusivity
ε
.
Determine the characteristic
distance L downstream from the point of discharge at which the wastewater plume reaches
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 Spring '09
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 CMFR

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