10 most difficult light riddlesLight quiz
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.
In astronomy, a moving line that divides the daylit side and the dark night side of a planetary body is called...
a circle of latitude
A terminator or twilight zone is a moving line that divides the daylit side and the dark night side of a planetary body. A terminator is defined as the locus of points on a planet or moon where the line through its parent star is tangent. An observer on the terminator of such an orbiting body with an atmosphere would experience twilight due to light scattering by particles in the gaseous layer.
What are the most luminous objects in the universe?
A quasar is an extremely energetic source of radiation powered by accretion disc around galaxy's central supermassive black hole. Quasars were much more common in the early universe, as all known quasars are extremely distant.
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.
How far away did the lightning strike if it took 3 seconds to hear the thunder?
approx. 0.3 km
approx. 1 km
approx. 3 km
approx. 9 km
Sound travels through air at 331.2 meters per second, so after 3 seconds it would travel approximately 1 kilometer.
Is the speed of light photons always constant?
Yes, but only in a vacuum.
No, it depends on the facility.
A speed of light is always constant.
None of the above
The speed at which light propagates through transparent materials, such as glass or air, is less than c. However, this "slowing of the light" is only due to the fact of photos being absorbed and re-emitted after a slight delay between atoms. When a photon is emitted, it's speed is always c. In exotic materials like Bose–Einstein condensates near absolute zero, the effective speed of light may be only a few metres per second.
What type of plasma is Sun composed of?
none of the above
The Sun is a nearly perfect sphere of hot plasma, with internal convective motion that generates a magnetic field via a dynamo process. Hot plasmas (thermal plasmas) have electrons and the heavy particles at the same temperature, i.e. they are in thermal equilibrium with each other. Cold plasmas (nonthermal plasmas) on the other hand have the ions and neutrals at a much lower temperature, whereas electrons are much "hotter".
How many typical stars can supernova be luminous as?
ten typical stars
one thousand typical stars
one million stars
one hundred billion stars
Supernovae are extremely luminous and often briefly outshine an entire galaxy. No supernova has been observed in the Milky Way since 1604, but they are often observed in distant galaxies.
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.