1139 Questions & Blanks Flashcards
When a light ray strikes a surface, it may be ______
transmitted, absorbed, reflected, or a combination of the three
Two reasons why household mirrors are back-surfaced
to make the silver last longer
to prevent necessary special attention to the silver
A refracted wave will ______
bend and change speed
Refraction causes an object under water to appear _______
nearer the surface and closer to the observer
A light ray entering a glass pane along the normal will ________
change speed only
A light ray traveling through a vacuum will _________
change neither speed nor direction
A light ray entering water at a 50degree angle with the normal will ________
change both speed and direction
A light ray striking a mirror will ______
change direction only
The index of refraction of a certain substance is ___________
inversely proportional to the speed of light in that substance
What did Willebrord Snell discover about the relationship between the angle of incidence and the angle of refraction?
(Nr)(sinOr) = (Ni)(sinOi) N = index of refraction O = angle of refraction/incidence
The common mirage that causes water to appear on the road on a hot day ________
results from refraction of light entering layers air at lower density
If sundown is listed in the almanac as 7:45 p.m., what exact time does the sun itself actually drop below the horizon.
7:41
The primary colors of light
red green blue
A white sheet appears white to our eyes because it
absorbs no light and reflects all colors of light
A ____________ results in a shorter focal length.
more sharply curved lens
An image is a real image if it can be ________
projected upon a screen
The word concave means _____
hollow
A __________ cannot be projected upon a screen
virtual image
What kind of lens is used to magnify objects?
convex
The brightness of an image is related to the ______________ and to the ____________
aperture of the camera
focal length of the lens
Many modern cameras focus by changing the ____
focal length of the lens
The largest refracting telescope in the world is __________
the Yerkes instrument in Wisconsin
Why did God create the sun, moon, and stars?
for signs and seasons, and for days and years
How do you calculate the total magnification of a compound microscope?
(magnification of objective)(magnification of eye lens)
What causes spherical aberration?
mirrors with spherical surfaces do not bring rays of light to a perfect focus
Parabolic reflectors used in automobile headlights ____
reflect all the light rays in the same direction
In Galileo Galilei’s hand, the telescope became a ___________
powerful tool for astronomy
Two major defects of Galileo’s telescope
chromatic aberration and poor field of view
