Physics II- Exam 4 – Flashcards
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Which of the following statements are true concerning electromagnetic radiation fields?
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The electric and magnetic fields are in phase with each other as they propagate through space.
The electric field at any point is perpendicular to the direction of wave travel.
The magnetic field at any point is perpendicular to the direction of wave travel.
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Which of the following statements are true concerning electromagnetic waves in a vacuum?
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Electromagnetic waves travel in a vacuum with a definite and unchanging speed.
When electromagnetic waves travel in vacuum, there is a definite, constant ratio between the magnitudes of the electric and magnetic fields.
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Suppose that an electromagnetic wave is traveling toward the east. At one instant at a given point, the electric field vector points upward. What is the direction of the magnetic field at this same given point and instant in time?
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South
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Which of the following statements are true regarding the electromagnetic spectrum?
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Radio waves have wavelengths on the order of meters.
Infrared radiation has long wavelengths.
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Which of the following statements are true concerning the reflection of light?
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The reflection of light from a rough surface is called diffuse reflection.
The reflection of light from a smooth surface is called specular reflection.
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Which of the following statements are true for an image formed by a plane mirror?
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The image formed by a plane mirror is always a virtual image.
The image always appears to be located the same distance behind the mirror as the object is located in front of the mirror.
The image formed by a plane mirror is always an upright image
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A wire loop is being pushed from an area with no B-field into an area where a uniform magnetic field exists (see figure). What is the direction of the induced current as the loop enters the uniform field?
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CCW
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A wire loop is being pulled through a uniform magnetic field at a constant velocity. What is the direction of the induced current?
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NONE
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A wire loop is being pulled away from a current-carrying wire. What is the direction of the induced current in the loop?
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CCW
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A solenoid with current moving through it is actually an electromagnet
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True
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A positive charge moves parallel to a wire. If a current is suddenly turned on in the wire, in which direction will the force act on the moving charge?
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To The Left
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What is the direction of the induced current if the B field suddenly decreases while the loop is in the region?
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Clockwise
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A positive charge enters a uniform magnetic field as shown. In what direction is the magnetic force?
<-- <--<--
<--<--<--
v
^
|
q
<--<--<--
<--<--<--
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Out Of Page
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What is the direction of the magnetic field at the center (point P) of the square loop of current?
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Into the page
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A horizontal wire carries a current and is in a vertical magnetic field. What is the direction of the force on the wire?
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Out of The Page
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Two straight wires run parallel to each other, each carrying a current in the direction shown below. The two wires experience a force in which direction?
^ ^
^ ^
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Toward Each Other
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A negative charge -Q is placed at rest near a magnet. Immediately after release the charge will begin to move due to the magnetic field exerting a magnetic force on it.
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False
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Diffuse reflection is reflection off a smooth surface
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FALSE
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Parallel light rays cross interfaces from air into two different media, 1 and 2, as shown in the figures below. In which of the media is the light traveling slower?
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Medium 2
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A man fails to spear a fish after many attempts with his fishing spear. In frustration, he pulls out his handy laser gun and shoots at the fish. Should he aim his laser at the fish, above the fish or below the fish image he sees in the water?
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At the fish Image he sees in the water
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An object is distance, d from the surface of a plane mirror (not curved). At what distance is the image from the surface of the mirror?
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d, The same distance
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A virtual image does have light rays passing through it, if you place a piece of paper at that location you would see the image.
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FALSE
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X-rays travel faster than radio waves because their wavelengths are shorter.
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FALSE
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Light has no mass, therefore it has no momentum.
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FALSE
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An EM wave is traveling due north (+y axis). The B-field is oscillating in the yz plane. In what plane is the E-field oscillating in?
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The xy Plane
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Magnetic B-field is up and steady
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No change in flux, no induced field, no induced current
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Magnetic B field is up and increasing
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Change in flux increases
Induced field down
Induced current CW
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Magnetic B field is up and decreasing
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Change in flux is down
Induced field is up
Induced current is CCW
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B field is down AND STEADY
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NO CHANGE IN FLUX, NO INDUCED FIELD, NO INDUCED CURRENT
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B field is down and increasing
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Change in flux down
Induced Field up
Induced Current CCW
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B field down and decreasing
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Change in flux up
Induced field down
Induced Current CW
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Mass of Electron
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9.11 x 10^-31 kg
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Charge of Electron
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1.602 x 10^-19 C
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Average rate wave carries energy
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I=.5Eo(c)(E)^2
