Physics Quiz For SSC CGL Exam 2019-20 : 7th November

Optical fibre work on the principle of Total Internal Reflection of Light. In optical fibre, when light traveling in an optically dense medium hits a boundary at a steep angle (larger than the critical angle for the boundary), the light is completely reflected. This is called total internal reflection.

Water Tank appear shallower when viewed from the top due to refraction of light. This virtual depth is known as Apparent depth.

Yellow colour is formed when Red and Green are mixed.

The phenomenon of raising outer edge of the curved road above the inner edge is to provide necessary centripetal force to the vehicles to take a safer turn and the curved road is called Banking of Roads.

A convex mirror provides for a larger field of view than a plane mirror. They are used whenever a mirror with a large field of view is needed. For example, the passenger-side rear view mirror on a car is convex.

It is difficult to fix a nail on a freely suspended wooden frame because when the wooden frame is not resting against a support, the frame and nails both move forward on being hit with a hammer. However, when the frame is held firmly against a support, and the nail is hit, an equal reaction of the support drives the nail into the frame. Thus based on Newton’s Third Law of Motion.

Zacharias Janssen was a Dutch spectacle-maker from Middelburg associated with the invention of the first Optical telescope. He is also credited for inventing the first truly compound microscope.

A H Taylor and Leo C Young are inventor of first true radar.

James Dewar was inventor of the thermos flask.

The laws which govern the motion of planets are called Kepler’s law of planetary motion.