Blog Tag SCIENCE

What is force?

A force is an agency that changes the shape or state of motion of a body or tries to change it.Force can change the state of motion of the body. Example: we apply force to move a stationary bicycle and also to stop a moving bicycle. The force is used to change the shape of the body. It can expand air to blow a balloon and also compress the air in a . . .

What is Energy?

Capacity of doing work by a body is called energy. Like work energy is also a scalar quantity and its unit is joule(J) The heat energy in the body is measured in calorie. 1 calorie =4.18 joule. The energy of atomic particles is measured in electron volts(eV). 1 eV=1.6 × 10-19 joule.   . . .

What is Power?

The rate of doing work is called power. If a body does W work in time t then its power is defined as, P= Work(W) ⁄ Time(t) Power=W/t We know that also W= F × d P=W/t =F × d/ t{ velocity v= d/t} = F× v Therefore, power is also expressed as P= Force × velocity. Unit of Power SI unit of power is watt(w). . . .

What is Work?

Work is defined as the product of force and displacement in the direction of force. Work on a body depends on two factors: Force applied on the body Net displacement of the body along the direction of force.  W= Force × Net displacement in the direction of force. Work is a scalar quantity. Unit of work SI unit of wor . . .

Why do stars twinkle?

The twinkling of star due to atmospheric refraction of starlight. The starlight, on entering the earth’s atmosphere, undergoes refraction continuously before it reaches the earth. The atmospheric refraction occurs in a medium of gradually changing refractive index. Since the atmosphere bends starlight towards the normal, the apparent position of t . . .

Energy in different forms

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Electrical energy and power

The flow of electric current in any circuit causes electric energy. Like, an electric bulb converts electrical energy into light energy, Electric fan converts electric energy into mechanical energy, Radio set converts electrical energy into sound energy. Electrical energy: We know that work done in flowing the charge q through a conductor having p . . .

Colour coding of electric wires in a cable

For convenience live, neutral and earth wire are provided with different colours. According to old convention of colour coding, live wire is red, neutral wire is black and earth wire is green in colour. How-ever in new international convention the respective colours for three wires are brown, light blue and green. . . .

What is Human Eye?

The human eye is one of the most valuable and sensitive sense organs. It enables us to see the wonderful world and the colours around us. On closing the eyes, we can identify objects to some extent by their smell, taste, sound they make or by touch. It is, however to impossible to identify colours while closing the eyes. Thus, of all the sense organs, t . . .

Difference between a real and virtual image

Real image Virtual image A real image is formed due to actual intersection of the reflected rays. A virtual image is formed when the reflected rays meet if they are produced backwards. A real image can be obtained on a screen. A virtual image cannot be . . .

What is a difference between a concave and convex mirror?

  Concave mirror   Convex mirror It is made by silvering the outer surface of a part of the hollow sphere, so reflection takes place from the inner surface. It is made by silvering the inner surface of a part of the hollow sphere, so reflection takes place from the bul . . .

Three-pin plug and socket

Usually a cable with three-pin plug at its one end is provided with any electrical appliances that connects it to the power supply. This plug is inserted into a three-holes socket fixed on a wooden or insulating power supply board. The bigger hole on top of the socket is connected to earth wire, right hole to the live wire and the left hole to the neutr . . .

What are applications of lenses?

Eye lens is a convex lens that forms the real and inverted image of any object on the retina. The lenses used in a camera, microscope and telescope are convex lenses. A magnifying glass is a convex lens used to watch minute objects. Spectacles are lenses used to correct the vision of our eyes. A concave lens is used in a Galillean telescope. . . .

What is a difference between mass and weight?

Comparision Mass Weight Definition Mass is the quantity of matter in a body regardless of its volume or of any forces acting on it. Weight is a measurement of the gravitational force acting on an object. Effect of gravity Mass i . . .

Differences between a planet and a satellite

Planet Satellite It is a heavenly body which revolves around the sun and rotates on its axis. It is a heavenly body which revolves around its planet and rotates on its own axis. It has a bigger size It has a smaller size There are . . .

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