Physics Quiz 5

On a rainy day, due to the Interference of light, small oil films on water show brilliant colours. Interference is a phenomenon in which two waves superimpose to form a resultant wave of the greater, lower, or same amplitude.

Robert Watson-Watt was a pioneer of radar technology. Although he did not invent the idea of radio detection, he was the first to prove it could work on a large scale. The world's first true radar system was invented by an American electrical engineer Albert Hoyt Taylor and an American radio engineer Leo C Young.

The atmosphere is heated mainly by the Radiation from the Sun. This radiation when passes through the atmosphere is absorbed by soil, plants, water bodies, the air molecules.

law of gravitation is defined by Isaac Newton in 1687. Newton's law of universal gravitation is usually stated as that every particle attracts every other particle in the universe with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centres.

Telescope and microscope can be distinguished by observing the length and size of the lens. In a telescope, the object lens has a large focal length and large aperture and the eye lens has small focal length and small aperture. The distance between the object lens and eye lens is adjusted to focus on the object situated at infinity. In a microscope, the object lens has a small focal length and short aperture and the eye lens used has a moderate focal length and large aperture. The object and eye lens are kept at a fixed distance apart, whereas the distance of the objective lens from the object is adjusted to focus an object.

Frequency determines colour, but wavelength is the easier thing to measure. These wavelengths range from 700 nm at the red end of the spectrum to 400 nm at the violet end. Visible light waves are the only electromagnetic waves we can see.

The kilowatt-hour (kWh) is a unit of energy equal to one kilowatt of power sustained for one hour and is commonly used as a measure of electrical energy. One kilowatt-hour is equal to 3600 kilojoules.

A particle moving with uniform speed may or may not have uniform velocity. This is because even if the direction of motion of the body changes, its velocity will get changed. Therefore as long as a body is moving in a constant direction as well as speed its velocity will remain constant.

The strongest force in nature is nuclear force, also called the strong nuclear interaction. It is the strongest of the four fundamental forces of nature.

Surface tension is the tendency of liquid surfaces at rest to shrink into the minimum surface area possible. The hair of a shaving brush clings together when removed from water due to Surface tension.