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प्रश्न
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उत्तर
We can find the relative density of a solid which floats on water by following the experiment.
Measuring the relative density of a cork
Choose a sinker and find its weight in water by suspending it in water.
Tie the solid to the string attached to the sinker and find its weight in air but sinker in water.
Remove the solid and tie it together with the sinker and suspend it in water and find the weight of the solid together with the sinker in water.
Record your observation as shown below:
Weight of sinker in water = x gf
Weight of sinker in water + solid in air = y gf
Weight of solid in air = (y - x) gf
Weight of solid + sinker in water = z gf
upthrust on solid in water = (y - z) gf.
The upthrust on in water also represents the weight of the water displaced by the solid. Relative density of solid = (weight of cork in air )/(weight of equal volume of water) Relative density = (y - x)/(y - z).
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संबंधित प्रश्न
When a piece of wood is suspended from the hook of a spring balance, it reads 70 gf. The wood is now lowered into water. What reading do you expect on the scale of spring balance?
A block of wood is so loaded that it just floats in water at room temperature. What change will occur in the state of floatation, if
(a) Some salt is added to water, (b) Water is heated?
Give reasons.
A body of volume V and density ρs , floats with volume v inside a liquid of density ρL. Show that `"v"/V = ρ_s/ρ_L` .
A body floats in a liquid A of density ρ1 with a part of it submerged inside the liquid, while in liquid B of density ρ2 it is totally submerged inside the liquid. The densities ρ1 and ρ2 are related as :
A weather forecasting plastic balloon of volume 15 m3 contains hydrogen of density 0.09 kg m-3. The volume of equipment carried by the balloon is negligible compared to its own volume. The mass of an empty balloon alone is 7.15 kg. The balloon is floating in air of density of 1.3 kg m-3. Calculate:
(i) The mass of hydrogen in the balloon,
(ii) The mass of hydrogen and balloon,
(iii) The total mass of hydrogen, balloon and equipment if the mass of equipment is x kg,
(iv) The mass of air displaced by balloon and
(v) The mass of equipment using the law of floatation.
What fraction of metal of density 3400 kgm-3 will be above the surface of mercury of density 13600 kgm-3, while floating in mercury?
A test tube weighing 17 gf, floats in alcohol to the level P. When the test tube is made to float in water to the level P, 3 gf of the lead shots are added in it. find the R.D. of alcohol.
If you put one ice cube in a glass of water and another in a glass of alcohol, what would you observe? Explain your observations.
Where do we use lactometers?
Assertion (A): Lactometer is used to check the purity of milk.
Reason (R): Lactometer measures the cream content of milk.
