Practice MCQ Questions and answers on Physics-GK

A mirage is a naturally occurring optical illusion or phenomenon in which light rays are bent due to refraction in layers of air of varying density. The image usually is upside down, enhancing the illusion that the sky image seen in the distance is really a water or oil puddle acting as a mirror.

One can distinguish a telescope from a microscope by observing length and size of the lens.

Electron microscope works on the principle of Wave Nature of electrons. Electron microscopes use an electron beam instead of visible light and an electron detector instead of our eyes. An electron beam allows us to see at very small scales because electrons can also behave as light due to its wave nature.

Holography is a photographic technique that records the light scattered from an object, and then presents it in a way that appears three-dimensional.

Optical fiber works on the principle of total internal reflection.
The Total Internal Reflection is the phenomenon in which the complete reflection of a light ray reaching an interface with a less dense medium when the angle of incidence exceeds the critical angle.

Condenser -Objective lens -Body tube -Eyepiece is the correct sequence of passage of light in a compound microscope.

In a Cinema hall, the distance between the projector and the screen is increased by 2%. Then the intensity of illumination on the screen is decreased by 4%.

Simple microscope - light microscope consisting of a short focus single convex lens is used to produce an enlarged image. The magnifying glass was invented by Roger Bacon in 1250. In the original ‘simple’ microscopes, a single light path went through the object viewed and one lens, increasing the visibility of the object by some amount (magnification). (One light path, one lens = simple microscope) Compound refers to the fact that in order to enlarge an image; a single light path passes through a series of lenses in a line. Each lens magnifies the image over the previous one. (One light path, multiple lenses = compound microscope) Usually, a modern compound microscope has multiple lenses within the eye tube, and a series of three or four objective lenses on the ‘head’ which can be rotated into place. The image produced is a two dimensional (2-D) image.

Person who is colourblind cannot distinguish between red and green.

Optical communication utilizes the principle of total reflection. When the injection angle of light satisfies certain conditions, light can form total reflection in the optical fiber, thereby achieving the purpose of long-distance transmission.