Homework 1 Flashcards
How is a Joule dened in terms of other units?
W * s
(Watts times seconds) This is derived from Power (Watts) = J/s
If a laser delivers 30 W of power to a target over 2 seconds, how much energy does it deliver to the target?
60 Joules
(use equation Power = J/s)
(use equation Power = J/s)
How is a Watt defined in terms of other units?
J/s
The human body produces about 100 W of heat energy per time. How much heat energy does the human body emit in an hour? Recall that an hour has 3600 seconds.
360 kJ
If a lightbulb produces 100 J of heat and light energy while on for 10 seconds, how much electrical power does the lightbulb consume?
10 W
What was James Watt’s primary contribution?
Making the steam engine much more efficient
What is the unit for energy?
Joule
Who was credited with starting the industrial revolution with their invention?
James Watt
Which of the following was responsible for the industrial revolution?
A. James Watt
B. Scientific Revolution
C. Abundant coal
D. All of the above
D.
What is the unit for power?
Watt
Who discovered that mechanical work gets converted to heat, thereby establishing the law of conservation of energy?
James Joule
By what process does air that is in contact with the Earth’s surface get heat?
Conduction
When a mass exchanges energy with a faraway mass by sending photons to it, what do we call this?
Radiation
When energy moves from one place to another because a mass carries that energy there, what do we call this?
Convection
Which of the following is an example of conduction?
A. warm hands by the fireplace
B. hot air balloon rises
C. burn hand on hot pan
D. the Sun heating the Earth
C.
Which of the following is an example of radiation?
A. feeling cold with hand on frosty window
B. burn hand on hot pan
C. hot air balloon rises
D. Warm hands by the fireplace
D.
Where does convection move energy into, out of, or within the Earth?
A. within the atmosphere
B. from the surface to the atmosphere
C. all of the other answers
D. from the Sun to the Earth
E. from the Earth to space
A.
Which of the following is an example of convection?
A. the Sun heating the Earth
B. hot air balloon rises
C. burn hand on hot pan
D. warm hands by the fireplace
B.
Where does conduction move energy into, out of, or within the Earth?
A. all of the other answers
B. from the Earth to space
C. from the surface to the atmosphere
D. within the atmosphere
E. from the Sun to the Earth
C.
By what process does energy from the Sun get to Earth’s surface?
Radiation
When a mass exchanges energy with an adjacent mass by jiggling against it, what do we call this?
Conduction
By what process does a blob of hot air move its heat from Earth’s surface up into the atmosphere?
Convection
Why does a small piece of burning paper float up into the air?
Convection
Where does radiation move energy into, out of, or within the Earth?
A. from the surface to the atmosphere
B. within the atmosphere
C. all of the other answers
D. from the Sun to the Earth
E. from the Earth to space
C.
