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प्रश्न
Explain the following :
A balloon filled with hydrogen rises to a certain height and then stops rising further.
उत्तर १
The reason is that the density of air decreases with altitude. Therefore, as the balloon gradually goes up, the weight of the displaced air (i.e. uphrust) decreases. It keeps on rising as long as the upthrust exceeds its weight. When upthrust becomes equal to its weight, it stops rising.
उत्तर २
A balloon filled with hydrogen has low density than air so it rises over the air but as height increases density of air decreases and at a certain height the density of hydrogen in balloon and density of air become equal. And as there is no density difference there is no pressure difference also and hence balloon stops rising further.
संबंधित प्रश्न
Complete the following sentence :
An empty tin container with its mouth closed has an average density equal to that of a liquid. The container is taken 2 m below the surface of that liquid and is left there. Then the container will ____________ .
A bunch of feathers and a stone of the same mass are released simultaneously in air. Which will fall faster and why? How will your observation be different if they are released simultaneously in vacuum?
A piece of brass weighs 175 gf in air and 150 gf when fully submerged in water. The density of water is 1.0 g cm-3.
(i) What is the volume of the brass piece? (ii) Why does the brass piece weigh less in water?
A body weighs W gf in air and W1 gf when it is completely immersed in water. Find: (i) Volume of the body, (ii) Upthrust on the body and (iii) Relative density of the material of the body.
Explain why an iron nail floats on mercury, but it sinks in water.
Hint : Density of iron is less than that of mercury, but more than that of water.
Explain the following :
As a ship in harbour is being unloaded, it slowly rises higher in water.
A block of wood of mass 24 kg floats on water. The volume of wood is 0.032 m3. Find:
- the volume of block below the surface of water,
- the density of wood.
(Density of water = 1000 kg m−3)
A solid body weighs 2.10 N. in air. Its relative density is 8.4. How much will the body weigh if placed
(1) in water,
(2) in liquid of relative density 1.2?
Select the correct option:
A body has density 9.6 gcm -3. Its density in SI system is:
