Physics - Study Mode

[#1241] Mist is caused by
Correct Answer

(C) Water vapour at low temperature

Explanation

Solution: Mist is a phenomenon caused by small droplets of water suspended in air. It can occur as part of natural weather or volcanic activity, and is common in cold air above warmer water, in exhaled air in the cold, and in a steam room of a sauna. It can also be created artificially with aerosol canisters if the humidity conditions are right. The only difference between mist and fog is visibility. Mist usually occurs near the shores, and is often associated with fog. Mist can be as high as mountain tops when extreme temperatures are low. Freezing mist is similar to freezing fog, only the density is less and the visibility greater.

[#1242] Which colour is the complementary colour of yellow ?
Correct Answer

(A) Blue

Explanation

Solution: Blue is the complementary colour of yellow.

[#1243] In sunlight a rose appears red. In green light, the same rose appears
Correct Answer

(B) Black

Explanation

Solution: Any object which allows light to pass through it is known as a transparent object. The colour of any transparent object is the colour of the light transmitted by it. A red rose appears red in white light because it absorbs all colours except red. However, when seen in green light, it looks black because the red colour of the rose is absorbed by the green light.

[#1244] When the Sun is near the horizon during the morning or evening, it appears reddish. The phenomenon that is responsible for this observation is
Correct Answer

(D) Scattering of light

Explanation

Solution: The red colour in the sky at sunset (and sunrise) is due to an effect called Rayleigh scattering. There is a similar form of scattering called Mie scattering which is responsible for the white colour of clouds.

[#1245] Which combination of colour is the most convenient during day and night time ?
Correct Answer

(D) Red and green

Explanation

Solution: Red and green is the most convenient combination during day and night time because of very precise visibility.