Tag: forces in fluids

Questions Related to forces in fluids

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

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

  1. True

  2. False

Show answer
Correct Option: A
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. 

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

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

  1. True

  2. False

Show answer
Correct Option: A
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

Hydrometer is used to measure 

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

  1. Pressure

  2. Weight

  3. Density

  4. Mass

Show answer
Correct Option: C
Explanation:

Hydrometer is an instrument used for measuring the density of liquids.

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 

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

  1. remains same

  2. level decreases

  3. level increases

  4. first increase ans decrese

Show answer
Correct Option: A

Hydrometers are used to serve what purpose?

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

  1. For determining density of liquid

  2. Pressure measurement

  3. Viscosity measurement

  4. None of the above

Show answer
Correct Option: A
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

The densities of objects P,Q,R and S are ${200 kg/m^3}$, ${450 kg/m^3}$, ${1200 kg/m^3}$  and ${785 kg/m^3}$ respectively. Which one of these objects will sink when dipped in a bucket of water?

physics forces in fluids experimental verification of archimedes' principle archimedes' principle archimedes' principle and its applications

  1. P

  2. Q

  3. R

  4. S

Show answer
Correct Option: C
Explanation:

Answer is C.

According to the laws of flotation, the more denser liquid will sink below and the less dense material will float.
In this case, the object R has the maximum density of $1200kg/{ m }^{ 3 }$.
Therefore, object R will sink when dipped in a bucket of water.

A piece of wood floats in water, completely inside it. What happens when it is dropped in ethanol?

physics forces in fluids experimental verification of archimedes' principle archimedes' principle archimedes' principle and its applications

  1. It floats higher

  2. Stays as before

  3. It sinks

  4. It sinks first and then rises

Show answer
Correct Option: C
Explanation:

Since , the ethanol is less denser than the water.Therefore, a piece of wood floating completely in water will sink in the ethanol.

As the density of a series of liquids increases, the upthrust on the iron rod submerged

physics forces in fluids experimental verification of archimedes' principle archimedes' principle archimedes' principle and its applications

  1. Increases

  2. Decreases

  3. Remains constant

  4. Noting can be said

Show answer
Correct Option: A
Explanation:

As the density of liquid increases & so does the buoyant force on the submerged rod which will result in increase in upthrust.