10 most difficult optics riddlesOptics quiz
What is a Fata Morgana?
a chemical reaction
an optical phenomenon
an optical illusion
The Fata Morgana occurs because rays of light are bent when they pass through air layers of different temperatures in a steep thermal inversion, where an atmospheric duct has formed. It significantly distorts the object on which it is based, often such that the object is completely unrecognizable. The Fata Morgana may be seen on land or at sea, in polar regions, or in deserts. It may involve almost any kind of distant objects, including boats, islands, and the coastline.
What is the phenomenon occurring at the rainbow?
reflection, refraction and dispersion
diffraction and refraction
A rainbow is a meteorological phenomenon that is caused by reflection, refraction and dispersion of light in water droplets resulting in a spectrum of light appearing in the sky. It takes the form of a multicoloured circular arc. Rainbows caused by sunlight always appear in the section of sky directly opposite the sun.
What term would photographers use to describe the quality of blurred part of the photo?
Bokeh has been defined as "the way the lens renders out-of-focus points of light". It can be good or unpleasant, depending on the lens aberrations and aperture shape. The term comes from Japanese for "blur".
In what process sky colors (including blue sky and red sun) are created?
Rayleigh scattering, named after the British physicist Lord Rayleigh (John William Strutt), is an elastic scattering of light or other electromagnetic radiation by particles much smaller than the wavelength of the radiation.
The bright circle around the Sun seen in the picture is known as a halo. What causes it?
refraction of light in ice crystals
refraction in the lens of the eye or lens
refraction of light in water drops
reflections from the water surface
Halo is the name for a family of optical phenomena produced by light interacting with ice crystals suspended in the atmosphere. Halos can have many forms, ranging from colored or white rings to arcs and spots in the sky. Among the best known halo types are the circular halo (properly called the 22° halo), Other common optical phenomena involving water droplets rather than ice crystals include the glory and the rainbow.
A person who has 4 types of color receptors is called ...
Such people do not exist
Man is usually sensitive to about 500,000 colors. Tetrachromacy is the condition of possessing four independent channels for conveying color information, or possessing four types of cone cells in the eye. Organisms with tetrachromacy are called tetrachromats which can see up to 99 million shades.
This optical phenomenon, appearing on misty mountainsides, is called...
A Brocken spectre or mountain spectre, is the apparently enormous and magnified shadow of an observer, cast upon the surfaces of clouds opposite the sun. The head of the figure is often surrounded by the glowing halo-like rings of a glory—rings of coloured light that appear directly opposite the sun when sunlight meets a cloud of uniformly-sized water droplets. The phenomenon can appear on any misty mountainside or cloud bank.
Which of the following is the worst for eyesight during a sunny day?
wearing sunglasses with UV filter
wearing sunglasses without UV filter
not wearing sunglasses at all
wearing sunglasses inside buildings
Wearing sunglasses without UV filter causes the pupils to dilate and eyes to absorb more UV rays than they normally would without the sunglasses. Hence, it's much better not to wear sunglasses at all, than to wear ones without UV filter.
What kind of lens was most likely used for this photo?
fixed focal length
Such shallow depth-of-field is possible with lens of large aperture size (small f-number). The large aperture is a typical feature (and advantage) of a fixed focal length lens. The photo was taken with a 50mm f/1.4 lens.
Which of the following camera lenses is typically more expensive?
The smaller the f-number, the larger relative aperture there is, and that means more light for the exposure. Each aperture has half the light gathering area of the previous one.