Title: Exam 2
Course: SGRD 105 Microgrids and Renewable Energies > Section: SGRD 105 Microgrids and Renewable Energies

Q: Wind power is proportional to
- windspeed
- windspeed squared
- windspeed cubed
- inverse windspeed
A: windspeed cubed

Q: Doubling turbine blade diameter changes the power available by a factor of
- 4
- 2
- 1/2
- 1/4
A: 4

Q: The total installed wind power capacity in the U.S. is
- 6 MW
- 100 MW
- 60 MW
- 2 MW
A: 60 MW

Q: The power produced by a generator depends on
- length of armature coil
- magnetic field strength
- rate of motion between field and armature
- all of the above
A: all of the above

Q: When and the shaft of and induction machine rotates faster than the synchronous speed it operates as a
- motor
- generator
- transformer
- capacitor
A: generator

Q: At the top of the Earth’s atmosphere the total solar power per unit area is
- 3.8 × 10^20 MW
- 1380 W/m^2
- 1000 W/m^2
- 60 Hz
A: 1380 W/m^2

Q: A rule of thumb for good performance of a PV array is set the tilt angle to
- zero (horizontal)
- 90◦ (vertical)
- site latitude
- site latitude − 45◦
A: site latitude

Q: For photovoltaic semiconducting materials, what source of energy moves charge carriers across the band gap
- mechanical
- thermal
- chemical
- solar
A: solar

Q: Efficiency of commercially available crystalline silicon PV cells are around
- 100 %
- 60 - 80 %
- 30 - 50 %
- 15 - 20 %
A: 15 - 20 %

Q: The operating point of a PV array is the voltage and current where
- power delivered is maximum
- power delivered is minimum
- load curve intersects the I-V curve
- slope of the load curve is minimum
A: load curve intersects the I-V curve

Q: Energy in water can take the form of
- gravitational energy
- pressure energy
- kinetic energy
- all of the above
A: all of the above

Q: The energy per unit weight of water has the physical dimension of length and is called the
- specific weight
- head
- energy density
- flow rate
A: head

Q: A hydrokinetic system utilizes
- velocity head of free flowing water
- elevation head established by a dam
- kinetic energy of jets which turn an impulse turbine
- steam driven turbine
A: velocity head of free flowing water

Q: Water is flowing velocity of 2.0 m/s in a pipe with cross sectional are of 0.03 m2 has a volume flow rate of
- 0.06 m^3/s
- 6.0 m^3/s
- 1.5 m^3/s
- 0.015 m^3/s
A: 0.06 m^3/s

Q: Axial flow hydrokinetic turbines have a rotation axis
- perpendicular to the current
- parallel to the current
- oriented due north
- oriented due east
A: parallel to the current

Q: An ideal battery is a source of constant
- voltage
- current
- power
- capacity
A: voltage

Q: As a lead acid battery is discharged, the cell voltage
- increases
- stays the same
- decreases
A: decreases

Q: In general, as discharge rate increases, battery capacity
- increases
- stays the same
- decreases
A: decreases

Q: Deep cycle lead acid batteries are appropriate for energy storage because they
- are designed to withstand slow, deep discharges
- have long cycle lifetimes for deep discharges
- are designed for short bursts of high current and very shallow discharge
- both A and B
A: both A and B

Q: What current does a 200 Ah battery deliver at a discharge rate of C/20?
- 10 A
- 20 A
- 0.1 A
- 0.4 A
A: 10 A