It is a “heavier than air” machine and flies in air on the principle of kite. Two forces lift (tending to lift the plane vertically upward) and drags (tending to take the plane in direction of the wind) are cause by relative velocity of wind and plane.
Lift can be increased by increasing the relative speed of wind, which is done by making the plane run on t& ground initially. As the plane moves forward, air flows over & below wings. The wings are designed in aerofoil section. Hence there is a pressure on the upper surface of the wing than on lower surface; winch gives rise to lift, making the plane airborne.
Air conditioning is the control of the weather within a chamber so to make it comfortable. Average comfort condition is temperature 18°C; relative humidity 60-65 per cent; air movement 25-75 ft/sec; introduction of 25 per purification of air and deodorizing.
Atomic-powered Submarine uses atomic energy and can function for very long periods without refueling. Atomic energy is liberated by an atomic pile attached to the submarine. The liquid circulating through the atomic pile becomes very hot and heat exchanger changes water into steam. This steam moves turbine, connected to the electric generator and the electricity produced by the generator dives the submarine.
Binocular is a pair of tubes fitted with an objective and an eye-piece in which magnified images of distant and near objects are seen. Binoculars for distant objects are called opera-glass. In prism binoculars, prisms are used for reducing the length of the scopes tube. It consists of a pair of right-angled totally reflecting prisms. One prism reverses the images, formed by the objective, upside down and the other from left to right.
The principle of persistence of vision is utilized in cinematography. Cinematography is an apparatus for projecting the pictures of moving objects on the screen. The instantaneous photographs of the successive positions of the moving body are photographed on a continuous film with the help of a special camera called movie camera, with an automatic shutter at the rate of nearly 16 per second. The film duly developed is projected intermittently with a similar shutter as above so that it opens when the film is stationary and closes when it jerks off.
It is a computer peripheral device that employs compact disk technology to store large amounts of digitized data for later retrieval.
This phone allows you to make a telephone call while on the move. It can be installed in vehicles or can be carried along.
A complicated electronic machine which can perform incredibly complex calculations at incomprehensible speeds. It was invented try Charles Babbage. It can do whatever we know but we have program it to how to order it to perform. A computer consists of a Central Processing Unit (C.P.U.) and a number of peripheral units. A computer does not do anything which a human being cannot do. Only that it does is much faster and accurately.
Davy’s Safety Lamp
Davy’s Safety Lamp is an oil lamp whose chimney is made of wire gauze. A part of the heat of the flame transmitted to the gauze goes out convection and radiation to the surrounding medium. If explosive gases methane burn inside the lamp, the fire does not come out as the wire absorbs most of the heat and the temperature outside does not reach nation point.
Diesel and Petrol Engines
Diesel and Petrol Engines are both internal combustion engines. In by the Can he vaporized diesel oil is mixed with the air which is ignited ex , eat of light compression in the engine cylinder. The mixture, on, makes the piston move. The speed and power of the engine are controlled by the amount of fuel supplied. Diesel engines are used in heavy road vehicles and for industrial purposes because it is economical operation. In a petrol engine an explosive mixture of vaporized petrol and air is ignited by sparks in the engine cylinder.
Dynamo is a device for converting mechanical energy into electrical energy. An electrical conductor moves across a magnetic field and electric current is induced. There is a powerful field magnet between the poles of which the armature is rotated. This mechanical energy is converted into electrical energy in the form of a current in the armature.
FAX Short for facsimile, it is a device that transmits pictures, drawings, text to a similar device at the receiving end, using telephone lines.
Heart Lung Machine:
It was invented by Dr. Dennis Melrose. It can take the normal function of the patient’s heart and lungs for 3 hours, to enable the surgeon to perform the delicate heart operation.
Water farm height falls on turbines, which are power units working on the principle of the water wheel, convert kinetic energy into mechanical energy. The turbines are connected with the armatures of dynamos and electricity is generated.
A partial vacuum is created inside the rubber tube by raising the level of the ink-filler which causes atmospheric pressure on the surface of the ink in the inkpot to push the ink into the tube.
Loudspeaker is an apparatus in which electrical energy is converted into sound energy. Its sound output is audible over a large area. Current is passed through a small voice of coil fitted to the apex of a conical paper diaphragm.
The voice coil travels in an angular gap over the middle arm of an E shaped permanent magnet. The voice coil is held in position in the centre of the gap by a flexible plate. When an alternating current passes through the coil the paper cone diaphragm vibrates at the same frequency and emits sound waves. Since the diaphragm is conical the sound waves emitted are much stronger than the sound waves produced before the microphone.
Laser or Light Amplification by Stimulated Emission of Radiation:
LASER is a device that harnesses light to produce an intense beam of radiation of a very pure, single color. The power of the beam can be low (as in a food store laser scanner which reads prices on packages) or high (as in lasers used to cut metals). The first laser was built in 1960.
Refrigerator consists of an insulated chamber in which edibles, medicines, etc. are kept to preserve their freshness. The motor compressor in a sealed pressurize container compresses a suitable gas which liquefies and expands. In this process it absorbs the latent heat from the surroundings and chamber. .
Radar (acronym of radio, angle, direction and range) was designs to detect and find the range of moving objects by transmitting a beam radio waves in the general direction of the objects and measuring the time taken for the reflected part of the wave (the echo) to return to the source of transmission. It gives the location, velocity, shape, size and nature of stationary and moving objects. Navigators on sea, air and moving vehicles, missiles and artificial satellites all use radar.
Tape Recorder is a system of recording and reproducing sound which uses a magnetic tape. When the recorder operates, the tape runs through a recording head having electromagnets. Sound waves pass through a microphone connected to the recording head. These sound waves cause the electric currents in the head to vary or fluctuate and thus set up a magnetic pattern. The pattern is impressed on an iron wire or metal-coated tape. When the tape is played back the magnetic pattern produces a varying electric current in the coils of the head. The varying electric currents are amplified and converted into sound waves by the loudspeaker.
Telegraph is a system of transmitting messages over a distance by electrical impulses through wires. By pressing a key at the transmitted station a circuit is closed and current flows through the conducting wire to the receiver. The dots and dashes of the Morse code are obtained.
It is an optical instrument used to see distant objects. It essentially consists of two lenses: objective which faces the object; the other eye-piece through which we see the image. The objective forms an image (invited) of the distant object in front of the eye-piece. This image acts like an object for the eye-piece. The latter forms an enlarged image of the former, thus giving us finally magnified image of the object.
Telephone is an apparatus used for the transmission of sound. It consists of a transmitter and a receiver connected by an electrical conductor. The transmitter is a carbon microphone, by means of which variable electrical impulses are caused to flow through the circuit. In the receiver these impulses flow through a pair of coil of wire and these produce sound.
It is a telegraph transmitter, with the help of which we can send more than 50 words per minute to several stations simultaneously without any strain to the operator and none whatsoever to the receiver. The Person at the sending station presses the key on the keyboard which is just like that of a typewriter, corresponding to a particular letter. At the receiving station the latter is recorded automatically.
It is the transmission of images of moving objects by radio waves. The scene to be transmitted or its image on a photo mosaic inside techno scope camera is scanned with the help of a fine beam of light inversing horizontally and vertically. The reflected pulses in the former se are picked up by photoelectric cells which convert light energy into help centric currents, or in the latter case, the photo mosaic with the are suntan electrical circuits generates varying currents. These currents with the help of valve amplifiers and are then made to “late the carrier waves from a transmitter. At the receiving station, the electrical vibrations are reconverted into light waves which are collected on the fluorescent screen of a cathode ray oscilloscope at the same rate with which they are generated at the sending station. With the help of the property of persistence of vision possessed by the eye one can see on the screen an exact photograph of the transmitted scene.
Thermos Flask is a double-walled bottle with silvering on the inner side of each wall with vacuum in between. Any substance, hot or cold put inside the flask remains so for a considerable period as there is no exchange of heat due to radiation because of the silvering or due to conduction or convection. Vacuum is a non-conductor and non-medium. Thermos flask is generally used for preserving hot tea, coffee, ice, drinks, etc.
Transformer is a device by which an alternating current is changed to a different voltage without any change in the frequency of the current. Step-up transformer increases the voltage and reduces the current. Step- down transformer decreases the voltage.