Introduction to Environmental Science
Mid Term exam Time: 90 minutes
Undergraduate and Graduate levels
Dr. Hezi Yizhaq
Part A
Mark the correct answer (4 points for each question)
1. The size of an atom is of order of ________
a) micron
b) nanometer
c) Angstrom
d) mm
2 Mark the correct sentence:
a) The shorter the wavelength – the lower the frequency and the higher the energy.
b) The longer the wavelength – the higher the frequency and the energy.
c) The shorter the wavelength – the higher the frequency and the energy.
c) The longer the wavelength – the lower the frequency and the higher the energy.
3. Mark the correct sentence:
a). Ultra-Violet light has a shorter wavelength than visible light.
b) Infra-Red light has a shorter wavelength than visible light.
c) Ultra-Violet light has an ionizing energy.
d) Infra-Red light has an ionizing energy.
4. Which of following waves aren't electromagnetic waves?
a). UV light.
b). Sound waves.
c). Gamma rays.
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d). Radio waves.
5. The wind speed ________
a) Increases with height
b) Decreases with height
c) Does not depend on height
d) Is constant in the boundary layer
6. The light intensity
a) Increases with the distance from the light source
b) Decreases with the distance from the light source
c) Does not depends on the distance from the light source
d) Decreases with the inverse of square of the light source
7. The North Star can change due to ________
a) Changes in Earth's eccentricity
b) Changes in Earth's obliquity
c) Changes in Erath's precession
d) Changes in Earth's orbit around the Sun.
8. The solar constant is close to
a) 1 w/m2
b) 10 w/m2
c) 1000 w/m2
d) 100 w/m2
9. The duration of solar spot cycle is:
a) 11 years
b) 1 year
c) 1 month
d) 100 years
10. If we double the distance from a light source then the light intensity will
a) Decreases by factor 2
2
b) Increase by factor 2
c) Decrease by factor 4
d) Decrease by factor
2
Part B
Decide if the assertion is True (T) or False (F) (3 points each)
11. During the night the direction of the breeze is from the sea into the land.
12. The Coriolis force is due the Earth's rotation .
13. The air density decreases as we increase the temperature.
14. The direction of the mountain valley breeze in the morning is up-valley.
15. During the period of increased number of solar spots the solar intensity decreases.
16. Watt is a unit of power.
17. All the electromagnetic waves move in the speed of light.
18. The eccentricity of a circle is 1
19. In the solar tower in Kibbutz Sammar the solar energy is used to activate a jet
turbine.
20. In the P type side of the PN junction some of the silicon atoms are replaced with
Boron atmos.
Part C
In order to answer the following questions you will need to use a calculator (5 points for
each question).
21. Calculate the amount of energy in kwh that a solar panel with dimension of 5x5 m
produces in 8 hours if the average power density is 400w/m2 and its efficiency is 20%.
22. Use the formula  
P
to calculate the air density where P=100000 Pascal, and
RT
T=200C.
R=287 is the Gas Constant for dry air .
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23. How many protons, neutrons and electrons are found in the atom
14
6
C?

v h
24. The wind speed dependence on height is given by the formula
   where 
v0  h0 
is the shear wind coefficient. Assume that   0.1 , find the wind speed at 10 height if
the wind speed at 3 m is 6 m/s.
Part D (10 points)
25. The table below contains results of an experiment to study the light intensity of a
point source light (which is proportional to the voltage V) as a function of the distance
from the source.
a) Plot V as a function of R. What is your conclusion from the graph?
b) Add a new variable that will give you a straight line if you plot V against the new
variable.
c) Plot the new graph and add the equation of the trend line.
R(cm)
V(mv)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
114
39
14
8.2
5.2
3.6
2.9
2.1
1.6
1.4
1
0.9
0.5
0.3
0.6
0.6
0.6
0.5
0.5
0.4
Good Luck!
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