Light Waves
This term describes the distance between two consecutive crests of a wave.
What is wavelength?
These tiny packets of light carry energy.
What are photons?
When light bounces off a surface, like a mirror, it is called this.
What is reflection?
This large, curved mirror at the back of a Newtonian telescope gathers and focuses incoming starlight.
What is the primary mirror?
This is the bending of light as it passes from one transparent material into another.
What is refraction?
Measured in hertz, this is the number of wavelengths that pass a point each second.
What is frequency?
This physicist explained the photoelectric effect by showing that light can behave as particles.
Who is Einstein?
By the law of reflection, the angle of incidence always equals this angle.
What is the angle of reflection?
This small, flat mirror redirects the focused light out to the side of the tube.
What is the secondary mirror?
This large lens at the front of a refracting telescope collects and focuses the light.
What is the objective lens?
When laser light bends around a thin hair and spreads out, this wave behavior is occurring.
What is diffraction?
In the photoelectric effect, photons with enough energy knock these negatively charged particles off a metal surface.
What are electrons?
Reflecting telescopes use a concave mirror of this curved shape to bring parallel light rays to a single focal point.
What is parabolic?
You look through this small lens on the side of the tube to see the final image.
What is the eyepiece?
Newton passed sunlight through a glass prism and refraction spread it into this rainbow of colors.
What is a spectrum?
The dark bands in a diffraction pattern are caused by this type of interference, where a crest meets a trough.
What is destructive interference?
Increasing this, the number of photons hitting the metal per second, ejects more electrons but doesn't make any of them more energetic.
What is intensity (photon flux)?
A large telescope mirror can be supported here, which a lens cannot be, and this is one reason mirrors can be built much bigger.
What is from behind (its back side)?
Blocking part of the primary mirror with a secondary mirror makes the image this, but it does not create a hole in it.
What is dimmer?
Different colors refract by different amounts, causing colored fringes around images in lens-based telescopes. This problem is called this.
What is chromatic aberration?
All light travels at the same speed in a vacuum, so if a light's wavelength gets shorter, its frequency does this.
What is increases?
A dim ultraviolet light can free electrons that a very bright red light cannot, because a photon's energy depends on this property, not on brightness.
What is frequency (or inverse of wavelength)?
Modern telescopes use this technology to reshape a mirror in real time to cancel out blurring from Earth's atmosphere.
What is adaptive optics?
If one primary mirror has twice the diameter of another, it has this many times the light-gathering area.
What is 4 (four times the amount)?
When white light passes through a prism or lens, this color of visible light is bent the most.
What is violet?