EGEE 101 – Exam #1 Midterm (Final Version) – Energy and Environmental Engineering – study material
What type of energy would each of the following be?
A barrel of oil
The sun beating down a solar panel
A piston moving in a car engine - correct answer ✔✔A barrel of oil - Chemical energy
The sun beating down a solar panel - Thermal energy
A piston moving in a car engine - Mechanical energy
A steel rod is initially very cold. If it is placed close to a fire, what happens?
A) The steel rod heats up.
B) The fire goes out.
C) Nothing happens. - correct answer ✔✔A) The steel rod heats up.
Which do you think is more efficient?
A) A jet engine that produces 70 units of work from 100 units of energy.
B) A vehicle that produces 50 units of work from 100 units of energy.
C) A water mill that produces 10 units of work from 100 units of energy. - correct answer ✔✔A) A jet
engine that produces 70 units of work from 100 units of energy.
There are a little more than 7.5 billion people on the planet today, but 2.5 billion people are using most
of the energy. The UN projects that human population will stabilize around 10 billion people by the year
2100 - an addition of 2.5 billion more people. How much would energy use increase by if 10 billion
people in 2100 are using the amount of energy 2.5 billion people are using today?
,A) 4x
B) 2x
C) 1x
D) 3x - correct answer ✔✔A) 4x
Through a combination of fertility rate and decreased poverty levels, a population's energy use is
growing exponentially 1% per year. How many years until the energy use doubles? - correct answer
✔✔69.3 years
t= 0.693/rate = 0.693/0.01 = 69.3 years
What energy growth rate per year would increase world energy use by 400% (2 doubling periods) in 80
years? - correct answer ✔✔1.7 per year
t=0.693/rate --> rate=0.693/time
rate= 0.693/40 = 1.7% per year
A wind turbine costs $10 million to construct and generates $1 million worth of electricity per year.
When has the wind turbine paid for itself (what is the pay-back period)? - correct answer ✔✔10 years
What do you think "embedded" energy is? - correct answer ✔✔The energy that goes into making
something.
What is the biggest use of energy in a home? - correct answer ✔✔heating and air conditioning
Kevin lives next to a power plant that burns coal. He wants to be more green, so he buys an electric car
that he can plug into his home electricity. What is powering Kevin's car? - correct answer ✔✔coal
Which has more kinetic energy?
A) An oil tanker moored at a terminal.
,B) A cubic mile of water (a lake) behind a 300 ft tall dam.
C) An atomic bomb in a silo in North Dakota.
D) A car moving at 120 mph across the Bonneville Salt Flats. - correct answer ✔✔D) A car moving at
120 mph across the Bonneville Salt Flats.
Which series goes from least energetic to most? - correct answer ✔✔Radio < infrared < ultraviolet < x-
rays
Which has more potential energy?
A) An oil tanker moving through the Suez Canal.
B) A cubic mile of water (a lake) behind a 300 ft tall dam.
C) An atomic bomb in a silo in North Dakota.
D) A car moving at 120 mph across the Bonneville Salt Flats. - correct answer ✔✔B) A cubic mile of
water (a lake) behind a 300 ft tall dam.
Which has more nuclear energy?
A) An oil tanker moving through the Suez Canal.
B) A cubic mile of water (a lake) behind a 300 ft tall dam.
C) An atomic bomb in a silo in North Dakota.
D) A car moving at 120 mph across the Bonneville Salt Flats. - correct answer ✔✔C) An atomic bomb
in a silo in North Dakota.
Which has more chemical energy?
A) An oil tanker moored at a terminal.
B) A cubic mile of water (a lake) behind a 300 ft tall dam.
C) An atomic bomb in a silo in North Dakota.
, D) A car moving at 120 mph across the Bonneville Salt Flats. - correct answer ✔✔A) An oil tanker
moored at a terminal.
The hot coffee heats the mug which heats my hands which are holding the mug. What method of heat
transfer is it? - correct answer ✔✔Conduction
What transformation occurs in the Sun? - correct answer ✔✔Nuclear to radiation
What transformation occurs in a computer? - correct answer ✔✔Electrical to light/sound
What transformation occurs in a lawn mower? - correct answer ✔✔Chemical to kinetic/mechanical
A power plant consumes 100 MJ of Energy, of which only 24 MJ are wasted heat. What is the efficiency?
- correct answer ✔✔0.76
Efficiency = (Etotal-Ewaste)/Etotal
= (100-24)/100 = 76%
A power plant converts 100 kJ of coal into 30 kJ of electrical energy. What is the efficiency? - correct
answer ✔✔30%
Efficiency = Eout/Etotal
= 30/100 = 30%
Your home converts 30 kJ of electrical energy into 15 kJ of useful energy (heat, electric) and 15 kJ of
wasted energy. What is your home's efficiency? - correct answer ✔✔50%
Efficiency = Eout/Etotal
= 15/30 = 50%
What type of energy would each of the following be?
A barrel of oil
The sun beating down a solar panel
A piston moving in a car engine - correct answer ✔✔A barrel of oil - Chemical energy
The sun beating down a solar panel - Thermal energy
A piston moving in a car engine - Mechanical energy
A steel rod is initially very cold. If it is placed close to a fire, what happens?
A) The steel rod heats up.
B) The fire goes out.
C) Nothing happens. - correct answer ✔✔A) The steel rod heats up.
Which do you think is more efficient?
A) A jet engine that produces 70 units of work from 100 units of energy.
B) A vehicle that produces 50 units of work from 100 units of energy.
C) A water mill that produces 10 units of work from 100 units of energy. - correct answer ✔✔A) A jet
engine that produces 70 units of work from 100 units of energy.
There are a little more than 7.5 billion people on the planet today, but 2.5 billion people are using most
of the energy. The UN projects that human population will stabilize around 10 billion people by the year
2100 - an addition of 2.5 billion more people. How much would energy use increase by if 10 billion
people in 2100 are using the amount of energy 2.5 billion people are using today?
,A) 4x
B) 2x
C) 1x
D) 3x - correct answer ✔✔A) 4x
Through a combination of fertility rate and decreased poverty levels, a population's energy use is
growing exponentially 1% per year. How many years until the energy use doubles? - correct answer
✔✔69.3 years
t= 0.693/rate = 0.693/0.01 = 69.3 years
What energy growth rate per year would increase world energy use by 400% (2 doubling periods) in 80
years? - correct answer ✔✔1.7 per year
t=0.693/rate --> rate=0.693/time
rate= 0.693/40 = 1.7% per year
A wind turbine costs $10 million to construct and generates $1 million worth of electricity per year.
When has the wind turbine paid for itself (what is the pay-back period)? - correct answer ✔✔10 years
What do you think "embedded" energy is? - correct answer ✔✔The energy that goes into making
something.
What is the biggest use of energy in a home? - correct answer ✔✔heating and air conditioning
Kevin lives next to a power plant that burns coal. He wants to be more green, so he buys an electric car
that he can plug into his home electricity. What is powering Kevin's car? - correct answer ✔✔coal
Which has more kinetic energy?
A) An oil tanker moored at a terminal.
,B) A cubic mile of water (a lake) behind a 300 ft tall dam.
C) An atomic bomb in a silo in North Dakota.
D) A car moving at 120 mph across the Bonneville Salt Flats. - correct answer ✔✔D) A car moving at
120 mph across the Bonneville Salt Flats.
Which series goes from least energetic to most? - correct answer ✔✔Radio < infrared < ultraviolet < x-
rays
Which has more potential energy?
A) An oil tanker moving through the Suez Canal.
B) A cubic mile of water (a lake) behind a 300 ft tall dam.
C) An atomic bomb in a silo in North Dakota.
D) A car moving at 120 mph across the Bonneville Salt Flats. - correct answer ✔✔B) A cubic mile of
water (a lake) behind a 300 ft tall dam.
Which has more nuclear energy?
A) An oil tanker moving through the Suez Canal.
B) A cubic mile of water (a lake) behind a 300 ft tall dam.
C) An atomic bomb in a silo in North Dakota.
D) A car moving at 120 mph across the Bonneville Salt Flats. - correct answer ✔✔C) An atomic bomb
in a silo in North Dakota.
Which has more chemical energy?
A) An oil tanker moored at a terminal.
B) A cubic mile of water (a lake) behind a 300 ft tall dam.
C) An atomic bomb in a silo in North Dakota.
, D) A car moving at 120 mph across the Bonneville Salt Flats. - correct answer ✔✔A) An oil tanker
moored at a terminal.
The hot coffee heats the mug which heats my hands which are holding the mug. What method of heat
transfer is it? - correct answer ✔✔Conduction
What transformation occurs in the Sun? - correct answer ✔✔Nuclear to radiation
What transformation occurs in a computer? - correct answer ✔✔Electrical to light/sound
What transformation occurs in a lawn mower? - correct answer ✔✔Chemical to kinetic/mechanical
A power plant consumes 100 MJ of Energy, of which only 24 MJ are wasted heat. What is the efficiency?
- correct answer ✔✔0.76
Efficiency = (Etotal-Ewaste)/Etotal
= (100-24)/100 = 76%
A power plant converts 100 kJ of coal into 30 kJ of electrical energy. What is the efficiency? - correct
answer ✔✔30%
Efficiency = Eout/Etotal
= 30/100 = 30%
Your home converts 30 kJ of electrical energy into 15 kJ of useful energy (heat, electric) and 15 kJ of
wasted energy. What is your home's efficiency? - correct answer ✔✔50%
Efficiency = Eout/Etotal
= 15/30 = 50%
