Advertisements
Advertisements
Question
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.
Solution
When tube floats in alcohol:
Weight of test tube = 17 gf
By law of floatation:
Weight of alcohol displaced by test tube =
Weight of test tube = 17 gf
When tube floats in water :
When test tube is made to float in water to the same level, as in alcohol then 3g lead stones are added in it.
∴ Weight of test tube = 17 gf + 3 gf = 20 gf
Weight of water displaced by test tube = 20 gf
Volume of alcohol displaced = Volume of water displaced
∴ R.D. of alcohol
`= "Weight of alcohol displaced"/"Weight of equal volume of water displaced"`
`= 17/20 = 0.85`
APPEARS IN
RELATED QUESTIONS
A body is held immersed in a liquid. (i) Name the two forces acting on the body and draw a diagram to show these forces. (ii) State how the magnitudes of two forces mentioned in part (i) determine whether the body will float or sink in liquid when it is released. (iii) What is the net force on the body if it (a) sinks and (b) floats?
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 test tube loaded with lead shots weighs 25 gf and floats upto the mark X in water. When the test tube is made to float in brine solution, it needs 5 gf more of lead shots to float upto level X. Find the relative density of brine solution.
A rubber ball floats in water with 2/7 of its volume above the surface of the water. Calculate the average relative density of the rubber ball.
State the principle of floatation. What can you say about the average density of a ship floating on water?
State the laws of flotation.
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.
