Choose the best possible answer for each question.
Closed book exam. No notes or help of any kind allowed.
Please submit your answers by email to ral5q@virginia.edu.
(A) re-emission of light by the phosphor on the inside of the bulb
after absorption of the ultraviolet.
(B) light directly emitted by the mercury vapor atoms when they
collide with the phosphor.
(C) light from accelerated phosphor atoms due to the applied
voltage.
(D) radiation from electrons accelerated by the applied voltage.
(A) smaller and brighter than a lens with less curvature.
(B) smaller and dimmer than a lens with less curvature.
(C) larger and dimmer than a lens with less curvature.
(D) larger and brighter than a lens with less curvature.
(A) 10%.
(B) 90%.
(C) 0.1%.
(D) none of the above
(A) the glass tube has a red coating.
(B) the wavelength of the electron is the same as red light.
(C) it is similar to the incandescent light bulb.
(D) the energy change of the electron is carried away by the red
light .
(A) has a larger aperture (larger diameter).
(B) contains a less highly curved lens (a longer focal length).
(C) has a smaller aperture (smaller diameter).
(D) contains a more highly curved lens (a smaller focal length).
(A) the sound is digitized and recorded on the CD as an array of
little permanent magnets.
(B) the sound is digitized and recorded on the CD as an array of
charged capacitors.
(C) the sound is digitized and recorded on the CD as an array of
little inductors.
(D) the sound is digitized and recorded on the CD as an array of
ridges and gaps.
(A) only two electrons can be in the same orbit if both have spin
up, but orbiting in opposite directions.
(B) only two electrons can be in the same orbit if both have spin
down, but orbiting in opposite directions.
(C) only two electrons can be in the same orbit if each has no
spin.
(D) only two electrons can be in the same orbit if one electron has
spin up and one has spin down.
(A) increase the size of the aperture to let more light into the camera.
(B) decrease the size of the aperture.
(C) increase the speed of the camera while you increase the size of
the aperture to let more light into the camera.
(D) none of the above will do it.
(A) electromagnetic waves contain moving electric charges and
charges produce magnetic fields when they move.
(B) while waves consisting only of electric fields are common and
travel indefinitely through space, they are known as "electric waves,"
not "electromagnetic waves."
(C) an electromagnetic wave must have a magnetic field that changes
with time to produce its electric field.
(D) electromagnetic waves always contain both electric charges and
magnetic poles, and magnetic poles are accompanied by magnetic fields.
(A) the magnetic field of the laser light exciting the water
molecules and then re-emitting the light in all directions, but of the
same wavelength.
(B) the electric field of the laser light exciting the water
molecules and then re-emitting the light as a laser beam in one
direction.
(C) the electric field of the laser light exciting the water
molecules and then re-emitting the light in all directions but of the
same wavelength.
(D) none of the above.
(A) the actual light rays do not pass through the image.
(B) the actual light rays do pass through the image.
(C) the actual light rays cannot be focused by a lens to form a real
image.
(D) the actual light rays can be focused but only into another virtual
image.
(A) act as a capacitor to accelerate ionized atoms to start electrons
flowing.
(B) act as an inductor to prevent current from being excessive.
(C) act as an inductor to keep current flowing reducing overall
power.
(D) act as a capacitor to store charge to prevent current from
being excessive.
(A) it will permanently magnetize the phosphor and no images will
be discernible.
(B) it will distort the images, but they will be discernible.
(C) images will not be distorted, but the color will be
unrealistic.
(D) images will not be distorted and color will be normal.
(A) an electric charge is moving at a constant velocity in a wire.
(B) an electric charge is moving at a varying velocity in a wire.
(C) an electric charge is moving in a circle in a vacuum at a fixed
speed.
(D) an electric charge is accelerating through space.
(A) the CD melts slowly.
(B) the microwave oven immediately burns out because the CD contains
metal and metals damage microwave ovens.
(C) nothing happens because the CD contains no water to absorb the
microwaves.
(D) the CD glows and emits sparks.
(A) red to orange to blue.
(B) red to blue to orange.
(C) orange to blue to red.
(D) blue to orange to red.
(A) the polar water molecules are depolarized and no longer absorb
the microwaves.
(B) the polar water molecules in the frozen stage cannot move.
(C) there are not enough polar water molecules.
(D) none of the above
(A) Co-axial cable will give you a clearer picture than a fiber
optic cable because no light gets in the co-axial cable.
(B) Co-axial cable gives about 170 channels and the fiber optic
cable can in principle give up to 50 million channels.
(C) Co-axial cable gives about 170 channels and the optic cable can
in principle give up to 50 thousand channels.
(D) A TV channel can transmit every 3 MegaHertz in the fiber optic
cable.
(A) the telescope is closer to the stars.
(B) the mirrors are even bigger because we dont have to worry about
wind effects.
(C) atmospheric effects due to changes in the speed of light are
eliminated.
(D) atmospheric effects due to changes in the frequencies of light
are eliminated.
(A) the point-like nature of the electron.
(B) the wave-like nature of the electron at sufficiently high electron
energies.
(C) the electron producing visible light while being accelerated.
(D) none of the above.
(A) shorter wavelengths of light are scattered more then longer
wavelengths by small particles in the air.
(B) shorter wavelengths of light are scattered less then longer
wavelengths by small particles in the air.
(C) shorter wavelengths of light are scattered more then longer
wavelengths by the water molecules in the clouds.
(D) shorter wavelengths of light are scattered less then longer
wavelengths by ionized particles in the air.
(A) can't bring all the colors to a focus at the same distance.
(B) can only form a virtual image and not a real image.
(C) causes light to spread apart rather than come together.
(D) will produce an inverted real image while a two element lens
will produce an upright real image.
(A) refraction and reflection of light in the water droplet and
refraction and reflection in the soap bubble.
(B) refraction in the water droplet and refraction and interference
in the soap bubble.
(C) refraction and reflection in the water droplet and refraction,
reflection and interference in the soap bubble.
(D) refraction, reflection, and interference in the water droplet
and refraction, reflection and interference in the soap bubble.
(A) 5 cm
(B) 20 cm
(C) 10000 cm
(D) 10 cm
(A) decreasing the f-number.
(B) increasing the shutter speed.
(C) decreasing the shutter speed.
(D) firing the flash twice or more.