Physics 1010 uvu final – Flashcards
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In science, a theory is
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a synthesis of a large body of well tested knowledge.
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In science, an educated guess is
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an hypothesis.
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For a scientific hypothesis to be valid, there must be a test for proving it
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wrong
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The language of science is
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mathmatics
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A person runs 5 km in 30 minutes. What is this runner's average speed?
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10 km/h
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The equilibrium rule, ?F = 0, applies to objects
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at rest and moving at constant velocity.
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Which concept is being illustrated when a tablecloth is quickly yanked beneath dishes
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inertia
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It takes 6 seconds for a stone to fall to the bottom of a mine shaft. How deep is the shaft?
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about 180 meters
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You are carrying a heavy couch through a doorway to help your neighbors move. However, the doorway is too narrow and your hand is between the door frame and the couch as it hits and comes to a stop. The concept that most explains why your hand is hurt is
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inertia
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Jogging Jake runs at 4 m/s along a train flatcar that moves at 10 m/s in the opposite direction. Jake's speed relative to the ground is
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6m/s
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The speedometer of an automobile reads
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instantaneous speed
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If an apple experiences a constant net force, it will have a constant
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acceleration
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Which of the following is true about sliding friction?
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It is proportional to the normal force.
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With negligible air resistance, a heavy and a light object fall
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with equal accelerations AND with the same increases in speed AND to the ground in equal times
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A motor boat crosses a river by keeping the bow pointed directly East while the boat's speedometer indicates 40 Km/hour. The current in the river is moving south at 30 Km/hour. How fast is the boat moving relative to the land?
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50 Km/hour
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When you rub your hands together, you
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cannot push harder on one hand than the other.
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When a cannonball is fired from a cannon, both the cannonball and the cannon experience equal
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amounts of force.
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Cars with airbags are safer in an accident than non-equipped ones because passengers hitting the airbag encounter
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longer time of deceleration.
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A 1-kg chunk of putty moving at 5 m/s collides with and sticks to a 5-kg bowling ball initially at rest. The bowling ball and putty then move with a momentum of
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5 kg m/s. (Hint: Momentum after = momentum before = mv = 1 kg x 5 m/s)
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You're driving down the highway and a bug spatters into your windshield. Which undergoes the greater change in momentum during the time of contact?
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both the same
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A 2-kg rifle that is suspended by strings fires a 0.01-kg bullet at 200 m/s. The recoil velocity of the rifle is about
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1 m/s
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No work is done by gravity on a bowling ball that rolls along a bowling alley because
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the force on the ball is at right angles to the ball's motion.
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Whereas impulse involves the time that a force acts, work involves the
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distance the force acts
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The work done to pump 50 kilograms of water up into a water tower is 5000 J. What is the potential energy of the water after it is raised compared to before it was raised?
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5000 J
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The work done on a 100-kg crate that is hoisted 4 m in a time of 2 s is
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4000 J. (Hint: Work = Fd = mgh = 100 kg x 10 m/s2 x 4m)
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The power required to lift a 100-kg crate a vertical distance of 4 m in a time of 2 s is about
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2000 W. (Hint: Power = Work/t = 4000 J / 2 s)
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Which requires the most amount of work on the brakes of a car?
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a) slowing down from 70 km/h to a stop. b) slowing down from 100 km/h to 70 km/h. c) equal amounts for either Answer: B
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According to the Law of Conservation of Energy:
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Energy cannot be created or destroyed.
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A piano mover uses a pulley system to lift a piano that weights 1000 newtons onto the second story, a distance of 5 meters. If each time the piano mover pulls the rope 1 meter the piano moves up 1/10 meter, what force must the mover use to pull on the rope?
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100 newtons
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A machine cannot multiply
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energy
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The original source of most of the energy we use is:
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the sun
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A moving object has
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speed, velocity, momentum,energy
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A car moves 4 times as fast as another identical car. Compared to the slower car, the faster car has
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16 times the Kinetic Energy.
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When an object is lifted 10 meters, it gains a certain amount of potential energy. If the same object is lifted 20 meters, its potential energy gain is
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twice as much
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The rotational inertia of an object is greater when most of the mass is located
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away from the rotational axis
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Horses that move with the fastest linear speed on a merry-go-round are located
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near the outside.
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When a twirling ice skater brings her arms inward, her rotational speed
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increases
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For an object to be in a state of total equilibrium with no change in its motion, what is required in addition to having no net Force acting on the object?
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The net Torque must be zero.
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A torque is a force
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multiplied by a lever arm
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The highest ocean tides occur when the Earth and Moon are to the Sun. .
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lined up with the Sun
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A rock is thrown upward at 50 degrees with respect to the horizontal. Neglecting air friction, as it rises, its horizontal component of velocity
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remains unchanged
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A rock is thrown vertically into the air. At the very top of its trajectory, the net force on it is
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its weight
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An object is thrown vertically into the air. At the very top of its trajectory, the velocity
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is zero.
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rojectile is launched at ground level at an angle of 15 degrees above the horizontal and lands down range. What other projection angle for the same speed would produce the same down-range distance?
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75 degrees
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A large and a small person wish to parachute at equal terminal velocities. The larger person will have to
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get a larger parachute.
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Earth satellites are typically more than 100 km high so as to be above the Earth's
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atmosphere
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Some communications and weather satellites always appear at the same place in the sky. This is because these satellites are
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orbiting the Earth with a 24-hour period.
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The magnitude of gravitational force on a satellite is constant if the orbit is
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circular
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Bonus question: If you are towing a car that weighs 20,000 newtons with a tow strap rated at 5,000 newtons, what is the shortest time you should take to accelerate to 36 kilometers/hour (10 meters/second) on a level surface if you don't want to break the strap?
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4 seconds
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You are carrying a heavy couch through a doorway to help your neighbors move. However, the doorway is too narrow and your hand is between the door frame and the couch as it hits and comes to a stop. The concept that most explains why your hand is hurt is
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Inertia
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An object in free fall (no air resistance) undergoes an increase in
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Speed
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Which has zero acceleration? An object
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at rest. AND moving at constant velocity. AND in mechanical equilibrium.
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If a constant net force acts on an object,
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It's volocity changes
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Two teams pull on a rope in a tug-of-war. Each team pulls with a 300 N force. What is the tension in the rope?
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300 N
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The rotational inertia of an object is greater when most of the mass is located
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Away from the rotational axis
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Which moves faster in m/s on a merry-go-round: a horse on the inside near the center or a horse on the outside near the outer rail?
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Outside horse
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A large and a small person wish to parachute at equal terminal velocities. The larger person will have to
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Get a larger parachute
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A scientific idea that is so well established that it cannot be questioned is
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an impossibility.
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One end of a rope is pulled with 200 N, while the opposite end also is pulled with 200 N. The tension in the rope is
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200 N
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When a twirling ice skater brings her arms inward, her rotational inertia
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decreases
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A floating object always displaces its own
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weight of fluid
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Before ice can form on a lake, all the water in the lake must be cooled to
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4 degrees C
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The pressure at the bottom of a pond does NOT depend on the
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surface area of the pond
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As the outside of a cold soda can becomes wet, the water inside becomes
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warmer
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Compared with radiation from the Sun, terrestrial radiation has a lower
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Frequency
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The pitch of a sound is mostly related to its
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Frequency
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The quality of a musical note has to do with its
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harmonics
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The fundamental force underlying all chemical reactions is
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Electrical
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The electrical force of attraction between an electron and a proton is greater on the
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neither
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According to Coulomb, two charged particles placed twice as close to each other experience a force
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four times as strong
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You can touch a 100,000-volt Van De Graaff generator with little harm because although the voltage is high, the relatively small amount of charge means there is a relatively small amount of
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Energy
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Immediately after two separated charged particles are released from rest, both increase in speed. The sign of charge of the particles is therefore
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Either of these
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Immediately after two separated charged particles are released from rest, both increase in acceleration. The sign of charge of the particles is therefore
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opposite
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To be safe in the unlikely case of a lightning strike, it is best to be inside a building framed with
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steel
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In a common dc circuit, electrons move at speeds of
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a fraction of a centimeter
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As more lamps are connected to a circuit in series, the current in the power source
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decreases
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Alternating current is normally produced by a
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generator
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A magnetic force acting on a beam of electrons can change its
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direction
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An electric force acting on a beam of electrons can change its
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energy and direction
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Electric power can be transmitted from one place to another without the need for connecting wires in between. This statement is
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true
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A step-up transformer has a turns ratio of one to ten. Neglecting slight losses, if 100 watts of power go into the primary coil, the power coming from the secondary coil is
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100 watts
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Which of these is not an electromagnetic wave?
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sound
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The source of all electromagnetic waves is
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vibrating charges
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When the shadow of the Moon falls on Earth, we have a
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solar eclips
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The Earth's atmosphere is transparent to most waves in the
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visible part of the spectrum
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Different colors of light correspond to different light
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frequencies
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The additive primary colors are
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red, green, blue
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The subtractive primary colors combine to determine "hue" and "saturation" in printed color pictures. What other color ink is needed to add "value" to printed pictures?
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black
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To say that a rose petal is red is to say that it
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reflects red
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The redness of a sunrise or sunset is due mostly to light that hasn't been
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scattered
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The shortest plane mirror in which you can see your entire image is
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half your height
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The distance of your image behind a plane mirror is equal to
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your distance in front of the mirror
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When you look at yourself in a pocket mirror, and then hold the mirror farther away, you see
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the same amount of yourself
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Light will almost always travel from one place to another along a path of least
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time
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Refraction occurs when a wave crosses a boundary and changes
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speed and direction
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When a pulse of white light is incident on a piece of glass, the first color to emerge is
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red
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Refraction causes the bottom of a swimming pool to appear
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closer to the surface than it actually is
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The twinkling of stars is a result of atmospheric
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refraction
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Rainbows are not usually seen as complete circles because
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the ground is usually in the way
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Colors seen when gasoline forms a thin film on water are a demonstration of
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interference
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The polarization axes of ordinary sunglasses are
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vertical
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The fact that light can be polarized shows that light is
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a transverse wave
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The red glow in the neon tube of an advertising sign is a result of
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excitation
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The model of light that best explains the photoelectric effect is the
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particle model
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In the photoelectric effect, the brighter the illuminating light on a photosensitive surface, the greater the
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number of ejected electrons
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The energy of a photon is proportional to its
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frequency
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All parts of a laser beam have the same
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frequency, speed, phase
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Bonus question: The ratio of a photon's energy to its frequency is
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Planck's constant.
