Tag: principle of floatation and its applications

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Multiple choice physics forces in fluids hydrometer and lactometer comparing density - relative density principle of floatation and its applications

Which of the following properties represent a hydrometer?
a. It helps to evaluate the relative density and purity of liquids.
b. The length of the hydrometer immersed in any liquid is directly proportional to the density of the liquid.
c. The relative density graduations on a hydrometer increase in the upward direction.
d. Water is regarded as a standard to find the relative density of any liquid using a hydrometer.

  1. a, b and c

  2. a and d

  3. a, b and d

  4. b and d
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Hydrometer is a device used for directly measuring the relative density of a liquid with respect to water and hence helps to test the liquids purity. A hydrometer tube submerges less in a liquid of higher relative density and more in a liquid of lower relative density with regard to water. Thus the graduations on the hydrometer test tube show increase in relative density in the downward direction as it sinks less in a liquid of higher relative density.

Multiple choice physics forces in fluids hydrometer and lactometer comparing density - relative density principle of floatation and its applications

Hydrometer is based on the principle of ___

  1. Principle of buoyancy

  2. Principle of floatation

  3. Pascals law

  4. Charle's law
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Hydrometer is based on the principle of floatation i.e., the weight of the liquid object displaced by the immersed portion of the hydrometer is equal to the weight of the hydrometer. 

Multiple choice physics forces in fluids hydrometer and lactometer comparing density - relative density principle of floatation and its applications

Match the following

1.Bulb filled with lead shots or mercury a. Increases sensitivity
2.The bulb helps the hydrometer to float b. Reduces center of gravity
3. Mercury c. Increases upthrust on the hydrometer
4. Narrow stem d. Gravity bulb

  1. 1-b, 2-d, 3-c, 4-a

  2. 1-b, 2-c, 3-a, 4-d

  3. 1-a, 2-d, 3-b, 4-c

  4. 1-d, 2-c, 3-b, 4-a
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Common hydrometer consists of three main parts the stem, the large bulb (floating bulb) and the small bulb filled with mercury or lead shots (gravity bulb). The floating bulb increases the upthrust on the hydrometer because when it submerges in the water completely it increases the weight of the water displaced. The smaller bulb is filled with lead shots or mercury which helps in lowering the center of gravity which enables the hydrometer to float vertically in the liquid. Thus the smaller bulb is called the gravity bulb. The narrow stem helps the hydrometer to sink effectively when dropped in a liquid with higher or lower relative density thus increasing the sensitivity of the hydrometer.

Multiple choice physics forces in fluids hydrometer and lactometer comparing density - relative density principle of floatation and its applications

Hydrometer is used to determine which of the following?

  1. Specific gravity of liquids.

  2. Boiling point of water.

  3. Specific heat of a matter.

  4. Specific humidity
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Hydrometer is a devide used to determine the specific density of liquids.

A hydrometer is usually made of glass, and consists of a cylindrical stem and a bulb weighted with mercury to make it float upright. The liquid to test is poured into a tall container and the hydrometer is gently lowered into the liquid until it floats freely. The point at which the surface of the liquid touches the stem of the hydrometer correlates to specific gravity. Hydrometers usually contain a scale inside the stem, so that the person using it can read specific gravity. 

Multiple choice physics forces in fluids hydrometer and lactometer comparing density - relative density principle of floatation and its applications

Hydrometers usually contain a scale inside the stem, so that the person using it can read specific gravity.Is the statement True or False

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
A hydrometer is usually made of glass, and consists of a cylindrical stem and a bulb weighted with mercury to make it float upright. The liquid to test is poured into a tall container and the hydrometer is gently lowered into the liquid until it floats freely. The point at which the surface of the liquid touches the stem of the hydrometer correlates to specific gravity. Hydrometers usually contain a scale inside the stem, so that the person using it can read specific gravity. 
Multiple choice physics forces in fluids hydrometer and lactometer comparing density - relative density principle of floatation and its applications

The principle of working of hydrometer is based on Archimedes's principle 

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

 archimedes principle states that weight lost by the body partially or fully immersed in a liquid is equal to the weight of the liquid displaced and hydrometer works on this principle.

so option (A) is correct

Multiple choice physics forces in fluids hydrometer and lactometer comparing density - relative density principle of floatation and its applications

A cube of ice has a iron piece frozen unside at.
The cube floats an a beakerfilled with water, when the ice melts then the level of water is beaker 

  1. remains same

  2. level decreases

  3. level increases

  4. first increase ans decrese
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

According to Archimedes' principle, the weight of the displaced water equals the weight of the ice and the iron. When the ice melts, the iron sinks and the water from the melted ice occupies a volume equal to its mass, resulting in no change in the total water level.

Multiple choice physics forces in fluids hydrometer and lactometer comparing density - relative density principle of floatation and its applications

Hydrometers are used to serve what purpose?

  1. For determining density of liquid

  2. Pressure measurement

  3. Viscosity measurement

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Answer is A

A hydrometer is an instrument used to measure the specific gravity (relative density) of liquids; that is, the ratio of the density of the liquid to the density of water. A hydrometer is usually made of glass and consists of a cylindrical stem and a bulb weighted with mercury or lead shot to make it float upright

Multiple choice physics upthrust in fluids, archimedes' principle and floatation applications of floatation principle of floatation and its applications when do objects float on water?

A cube of size 10 cm is floating in equilibrium in a tank of water. When a mass of 10 gm is placed on the cube, the depth of cube inside water increases by $\mathrm { g } = 10 \mathrm { m } / \mathrm { s } ^ { 2 }$ density of water $= 1000 \mathrm { kg } / \mathrm { m } ^ { 3 } )$

  1. 0.1 m

  2. 1 mm

  3. 1 m

  4. 0.31 m
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Let $x$ be the initial depth upto which the cube is sinked in water.

Let $d$ be the density of the cube
Then
$x\times 10 \times 10\times 1 \times g$
$=10\times 10 \times 10\times 1 \times g\times d$........(1) 
$\Rightarrow x=10d$
Let $x^1$ be the new depth, then 
$x^1\times 100 \times g=1000\times d \times g+10g$........(2)
subtracting (1) and (2) we get
$\Rightarrow 100x^1=10x+10$
$x^2-x= \frac{1}{10cm}=1mm$
Hence,
option $B$ is correct answer.