Physics - Light Unit
Describe how a mirage is produced.
The air near the ground is heated up by the sun. A few meters above the ground the air is much cooler. The different temperature of the air results in different densities for the layers of air. This results in each air layer having a different index of refraction! Total reflection occurs.
What condition must be met before total internal refraction can occur?
The light travels form denser (higher refractive index) medium to less dense medium with the incidence angle is greater than the critical angle.
What does a negative distance of an image signify?
Virtual image
What type of image do convex mirrors always form?
Virtual, upright and smaller image
What occurs when yellow light is combined with blue light?
White
What color does blue pigment subtract from white light?
Yellow
Which of the following is NOT a primary subtractive color?
blue
What is an additive primary color?
blue, red, green
When red light is compared with violet light in vacuum,
both travel at the same speed.
What are the primary subtractive colors?
cyan, magenta, and yellow
When light passes at an angle to the normal from one material into another material in which its speed is lower,
it is bent toward the normal to the surface.
Which of the following is a device that produces an intense, nearly parallel beam of coherent light?
laser
Which portion of the electromagnetic spectrum is used in a television?
radio waves
A highly polished finish on a new car provides a ____ surface for ____ reflection.
smooth; specular
The ____ of light can change when light is refracted because the wavelength changes.
speed
When a straight line is drawn perpendicular to a flat mirror at the point where an incoming ray strikes the mirror's surface, the angles of incidence and reflection are measured from the normal and
the angles of incidence and reflection are equal.
The farther light is from a source,
the more spread out light becomes.
If light waves are coherent,
they remain in phase.
In a vacuum, electromagnetic radiation of short wavelengths
travels as fast as radiation of long wavelengths.
Which of the following best describes the image produced by a flat mirror?
virtual, upright, and magnification equal to one
When light passes at an angle to the normal from one material into another material in which its speed is higher,
it is bent away from the normal to the surface.
Atmospheric refraction of light rays is responsible for which effect?
mirages
Light is NOT refracted when it is
striking a wood surface.
Which of the following is NOT an additive primary color?
yellow
Which is an example of refraction?
A fish appears closer to the surface of the water than it really is when observed from a riverbank.
Predict whether the light will be refracted or whether it will undergo total internal reflection when the cable is in the air.
If the incidence angle is greater than (/) then it will undergo total reflection and not refraction will occur
How is the brightness of a light source affected by distance?
It depends inversely distance square.
If you are reading a book and you move twice as far away from the light source, how does the brightness at the new distance compare with that at the old distance?
It is one-fourth