Practice MCQ Questions and answers on Physics-GK

Dispersion of light is the splitting of white light into its constituent colors due to the refractive index of the surface and the wavelength of the light.

In optics, a prism is a transparent optical element with flat, polished surfaces that refract light. At least two of the flat surfaces must have an angle between them. The exact angles between the surfaces depend on the application. The traditional geometrical shape is that of a triangular prism with a triangular base and rectangular sides, and in colloquial use “prism” usually refers to this type. A prism can be used to break light up into its constituent spectral colours (the colours of the rainbow). Prisms can also be used to reflect light, or to split light into components with different polarizations. Prisms are sometimes used for the internal reflection at the surfaces rather than for dispersion.

Blue + Yellow pigment yields the colour green.

Violet waves have the highest frequencies.

The splitting of different colours of light in a prism is disperson of light.

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.

Blue is the complementary colour of yellow.

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.

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.

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