Name State Established Area (in km2) |
1. Anshi National Park Karnataka 1987 250 |
2. Balphakram National Park more...
Endangered Species
We can define the endangered species as those/ which are on the verge of extinction. They are either few in numbers or threatened by the environmental consequence or by the predators. According to the International Union for Conservation of Nature (IUCN), the percentage of endangered species is 40% of the all organism, based on the sample taken. The most endangered species is Dhole, which is on the verge of extinction. There is legal provision for protection of endangered species in many countries of the world. For example, the Pandas, Philippines Eagle, Javan Tiger, Passenger Pigeon, Caribbean Monk Seal, etc are some of the species, which are on the verge of extinction.
There are many species, which are on the verge of extinctions. But, among them there are few species, which are considered as the most endangered one. Which one of the following is the most endangered species?
(a) Dhole
(b) Pandas
(c) Javan tiger
(d) Philippines Eagle
(e) None of these
Answer: (a)
Explanation
The species, whose population is very less, also there is a little chance of increasing their number in future, are known as endangered species. The most endangered species is Dhole, as the current world population of Dhole is estimated to be 2500.
In which one of the following states the Dalma Wildlife sanctuary is situated?
(a) UP
(b) Bihar
(c) Jharkhand
(d) Kerela
(e) None of these
Answer: (c)
Explanation
The Dalma wild life sanctuary is in the state of Jharkhand.
Buoyancy
When an object is immersed in liquid an upward force acts on it, which is called buoyancy. The buoyant force does not depend upon the weight of the object or the shape of the object, it only depends on the weight of the liquid displaced by the object. This principle is applicable to all the object of any density. If the density of the object is more than the density of the liquid, the object will sink. But if the density of the liquid is more than the object, the object will float on the surface of the liquid. On the other hand, if the density of the liquid and objects are equal, the object will float with half part immersed in the liquid.
Buoyancy
When an object is immersed in liquid an upward force acts on it, which is called buoyancy. The buoyant force does not depend upon the weight of the object or the shape of the object, it only depends on the weight of the liquid displaced by the object. This principle is applicable to all the object of any density. If the density of the object is more than the density of the liquid, the object will sink. But if the density of the liquid is more than the object, the object will float on the surface of the liquid. On the other hand, if the density of the liquid and objects are equal, the object will float with half part immersed in the liquid.
Find the weight of an object whose volume 45 m3 and density 2.4 gm/m3.
(a) 0.108kg
(b) 1.1 kg
(c) 2.4kg
(d) 3.2kg
(e) None of these
Answer: (a)
Explanation
Weight of an object is given by,
W = m x g
We can find the value of W by substituting the other parameters and we get the weight to be 0.108 kg.
Thomas throws a silver coin in the sea. The density of the coin is 0.985 gm/m3. Will the coin float on the surface of water or it will sink?
(a) Sink
(b) Float
(c) Float half immersed
(d) can't say
(e) None of these
Answer: (b)
Explanation
Since the density of the coin is less than the density of water, hence it will float on water.
Amount of Buoyancy
The amount of buoyancy of a body is determined by the body's specific gravity. Specific gravity is the ratio of the weight of a body to the weight of the water it displaces. Pure water has a specific gravity 1. The specific gravity of other objects is determined by finding the ratio of the density of the object to the density of the water. Objects with the gravity of less than 1 will float and the object with a specific gravity greater than 1 will sink.
Archimedes' Principle
From the above figure, we can observe that when a weight is hanged with the help of a spring balance, the weight is more in air and less when it is dipped into the liquid. This is because, when the weight is immersed into the liquid, the buoyant force acts on it in upward direction, which reduces its weight. The decrease in the weight is equivalent to the weight of the liquid displaced by the object immersed in it.
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Archimedes Principle
Archimedes of Syracuse (circa 287 BC - 212 BC), was a Greek mathematician, astronomer, philosopher, physicist and engineer. He was killed by a Roman soldier during the sack of the city, despite orders from the Roman general, Marcellus, that he was not to be harmed. Some historians of Mathematics consider Archimedes as one of the greatest mathematicians in history, along with possibly Newton, Gauss and Euler. Also, St. Lucy was from Syracuse. She died because her eyes was taken out with forks by the violent people.
Archimedes Principle
The concept was put on around 212 B.C., by the Greek scientist Archimedes. According to this principle, an object immersed fully or partially in the liquid is acted upon by the upward force, which is equivalent to the weight of the liquid displaced by the object.
Mathematically, if M is the mass of the liquid, its weight is given by:
W= M x g
If V is the volume of the liquid, andp is the density of the liquid, its mass is given by:
M = pxV
Hence, W = px V xg..
Atmospheric Pressure
Our atmosphere contains large volume of mixture of gases. These gas exert pressure on the objects form all directions. This pressure is called atmospheric pressure. The atmospheric pressure is maximum at the sea level and minimum on the top of the mountains. This is because the air volume is maximum on the sea level and minimum at the top of the mountain. Thus, as we go up the pressure goes on decreasing. The air pressure on the surface of earth is 101.3 kPa and on the surface of sea-level is 760 mm of Hg.
We can demonstrate the existence of atmospheric pressure with the help of the following activity:
Take a glass jar and fill it with the water up to the brim. Place a sheet of paper on its brim so that no air molecule remains inside. Now keeping the paper in its position, invert the jar in downward direction. You will observe that, the paper does not fall off, though the jar is full of water and exerting pressure in downward direction. This is because of the fact that, the atmospheric pressure acting on the paper in the upward direction, holding the paper sheet in its position. The upward pressure on the sheet is more than the downward pressure, hence it is not falling.
Pressure Inside Our Body
Our body contains liquid in the form of water and blood. These blood flow through the blood vessels and exert pressure on the wall of the vessels. This pressure is called blood pressure. Our body is balanced by the atmospheric pressure and blood pressure and hence we do not get crushed. Our body is so balanced by these pressures that we never feel discomfort. But if we go up high on the mountain where the pressure is very low, we start feeling uncomfortable and uneasy. Many people even start nose bleeding at higher altitude. This is because, due to the difference in the pressure at higher altitude the blood vessel in our body burst and bleeding starts.
Application of Atmospheric Pressure
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