Which of the following is used to split white light into different colours
In optics, a prism is a transparent optical element with flat, polished surfaces that refract light. At least two of the flat surfaces must have an angle between them. The exact angles between the surfaces depend on the application. The traditional geometrical shape is that of a triangular prism with a triangular base and rectangular sides, and in colloquial use "prism" usually refers to this type.
Question 82
A kilowatt-hour is unit of
Work is defined as a force acting through a distance (a length of space), energy is always equivalent to the ability to exert pulls or pushes against the basic forces of nature, along a path of a certain length. In the International System of Units (SI), energy is measured in joules, but in many fields other units, such as kilowatt-hours and kilocalories, are customary.
Question 83
The hydraulic brakes used in automobiles is a direct application of
Pascal's principle guarantees that the pressure is transmitted equally to all parts of the enclosed fluid system. This gives straightline braking unless there is a fluid leak or something to cause a significant difference in the friction of the surfaces. The hydraulic brake is an arrangement of braking mechanism which uses brake fluid, typically containing ethylene glycol, to transfer pressure from the controlling unit, which is usually near the operator of the vehicle, to the actual brake mechanism, which is usually at or near the wheel of the vehicle.
Question 84
Laser is a device to produce
In physics, two wave sources are perfectly coherent if they have a constant phase difference and the same frequency, and the same waveform. Coherence is an ideal property of waves that enables stationary (i.e. temporally and spatially constant) interference.
Question 85
Speed of sound is the greatest in
Sound travels faster in liquids and non-porous solids than it does in air. It travels about 4.3 times as fast in water (1,484 m/s), and nearly 15 times as fast in iron (5,120 m/s), than in air at 20 degrees Celsius.
Question 86
"Curie" is unit of
Curie, in physics, unit of activity of a quantity of a radioactive substance, named in honour of the French physicist Marie Curie. One curie (1 Ci) is equal to 3.7 x 1010 Becquerel (Bq). Radioactivity refers to the particles which are emitted from nuclei as a result of nuclear instability.
Question 87
Ultra violet radiations of the Sun do not reach the earth because, earth's atmosphere is surrounded by
The ozone layer absorbs 97-99% of the Sun's medium-frequency ultraviolet light (from about 200 nm to 315 nm wavelength), which potentially damages exposed life forms on Earth. Ozone is formed from dioxygen by the action of ultraviolet light and also atmospheric electrical discharges, and is present in low concentrations throughout the Earth's atmosphere. In total, ozone makes up only 0.6 parts per million of the atmosphere.
Question 88
The method of protecting iron from rusting, by coating a thin layer of Zinc is called
Galvanisation or galvanization (or galvanizing as it is most commonly called) is the process of applying a protective zinc coating to iron or steel, to prevent rusting.
Question 89
What is the maximum value of deforming force up to which a material shows elastic property and above which the material loses it
The Maximum Extent to which a solid may be stretched without permanent alteration of size or shape.
Question 90
When the speed of car is doubled, then what will be the braking force of the car to stop it in the same distance
Brake force, also known as Brake Power, is a measure of braking power of a vehicle. Suppose a car whose mass is 'x' and is braked from a speed of y km/hr to come to halt at a uniform retardation in z min. If the speed of the car is doubled in the same distance, then the braking force required to stop the car is four times the original speed i.e. '4v'. Note that all the parameters remain to be same.
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