CLASS 10
THE NECKLACE
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Helium
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Oxygen
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Hydrogen
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Nitrogen
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Detailed explanation-1: -Helium atoms are so light that they are able to escape Earth’s gravity! Helium that is bought in cylinders (like the ones used to fill your party balloons!) is produced by radioactive decay of thorium and uranium!
Detailed explanation-2: -Barring a large asteroid impact that can inject large swaths of the atmosphere into space, the only gases that regularly escape Earth’s atmosphere today are hydrogen and helium, the lightest elements in the universe.
Detailed explanation-3: -Helium balloons are pulled by gravity, as are all objects with mass. The reason they don’t fall is that there is another force acting on them, a buoyant force from air pressure that is equal to the weight of the air displaced by the balloon.
Detailed explanation-4: -Answer and Explanation: That is, the escape speed is 11.2 km/s. The helium atom needs this speed to leave the earth.
Detailed explanation-5: -Almost no hydrogen gas escapes Earth’s atmosphere. This is partly because hydrogen is reactive and exists almost exclusively in combination with other, heavier elements. Helium, too, is a gas.