Tag: archimedes' principle and its applications

Questions Related to archimedes' principle and its applications

Archimedes' major contribution / discovery was:

physics upthrust in fluids, archimedes' principle and floatation experimental verification of archimedes' principle archimedes' principle archimedes' principle and its applications

  1. Photoelectric effect

  2. Principle of buoyancy

  3. Wave theory of light

  4. Law of inertia

Show answer
Correct Option: B
Explanation:

Answer is B

Archimedes' principle indicates that the upward buoyant force that is exerted on a body immersed in a fluid, whether fully or partially submerged, is equal to the weight of the fluid that the body displaces. Because of this buoyancy a body is able to float or submerge over liquid surface.

An iron ball is weighed in air and then in water by a spring balance

physics upthrust in fluids, archimedes' principle and floatation experimental verification of archimedes' principle archimedes' principle archimedes' principle and its applications

  1. Its weight in air is more than in water

  2. Its weight in water is more than in air

  3. Its weight in same both in air and water

  4. Its weight is zero in water

Show answer
Correct Option: A
Explanation:

By Archimedes Principle, an object immersed(partially or fully) in a fluid experiences a loss in weight, which is given by the weight of the fluid displaced by the body.


For the given iron ball, the weight measured in air is $W _1 = (m _\textrm{ball}-\rho _\textrm{air}V _\textrm{ball})g$
Similarly, weight measured in water is $W _2 = (m _\textrm{ball}-\rho _\textrm{water}V _\textrm{ball})g$

We know that, $\rho _\textrm{water} > \rho _\textrm{air}$
Hence, $W _2 <W _1$
i.e., Weight measured in air is more than that in water.

A cylinder is made up of a material of density $1.5\ g\ cm^{-3}$ is immersed inside a liquid of density $1\ g\ cm^{-3}$. State whether the cylinder moves up or not

physics upthrust in fluids, archimedes' principle and floatation experimental verification of archimedes' principle archimedes' principle archimedes' principle and its applications

  1. Yes

  2. No

  3. Maybe

  4. Can't say

Show answer
Correct Option: B
Explanation:

Let the volume of cylinder be V

So weight of cylinder is $W=V\rho _{cylinder}g=1.5Vg$
Buoyancy force $F=V\rho _{liquid}g=V\times 1\times g=Vg$
Since weight is greater than buoyancy, $W>F$, so it will move downward.

$A$ and $B$ are two metallic pieces. They are fully immersed in water and then weighed. Now they show same loss of weight. The conclusion therefore is:

physics upthrust in fluids, archimedes' principle and floatation experimental verification of archimedes' principle archimedes' principle archimedes' principle and its applications

  1. $A$ and $B$ have same weight in air

  2. $A$ and $B$ have equal volumes

  3. The densities of the materials of $A$ and $B$ are the same

  4. $A$ and $B$ are immersed to the same depth inside water.

Show answer
Correct Option: B
Explanation:

Same loss of weight implies equal buoyant forces on the object which is equal to weight of liquid displaced i.e. both the bodies have equal volumes.

Two solids A and B Float is a liquid. It is observed that A floats with half its volume immersed and B floats with $2/3$ of its volume immersed. Compare the densities of A and B.

physics upthrust in fluids, archimedes' principle and floatation experimental verification of archimedes' principle archimedes' principle archimedes' principle and its applications

  1. $4:3$

  2. $2:3$

  3. $3:4$

  4. $1:3$

Show answer
Correct Option: C
Explanation:

$\dfrac { density\quad of\quad A }{ density\quad of\quad B } =\dfrac { density\quad of\quad immersed }{ Volume\quad of\quad B\quad immersed } =\dfrac { 1/2 }{ 2/3 } $

$\dfrac { density\quad of\quad A }{ density\quad of\quad B } =\dfrac { 3 }{ 4 } $

A piece of paraffin wax of density 0.9 g/cc floats on water.A layer of turpentine of density 0.87 g/cc is added on top of water until the wax is entirely submerged.The ratio of the volume of wax immersed in water to that in turpentine is 

physics upthrust in fluids, archimedes' principle and floatation experimental verification of archimedes' principle archimedes' principle archimedes' principle and its applications

  1. 3 : 13

  2. 87 : 90

  3. 90 : 87

  4. 3 : 10

Show answer
Correct Option: D
Explanation:

Buoyant force = weight of liquid displaced

hence $0.9V=1\times { V } _{ 1 }+0.87\times { V } _{ 2 }$
            & $V={ V } _{ 1 }+{ V } _{ 2 }$
               $0.9\left( { V } _{ 1 }+{ V } _{ 2 } \right) ={ V } _{ 1 }+0.87{ V } _{ 2 }$
               $0.9{ V } _{ 1 }+0.9{ V } _{ 2 }={ V } _{ 1 }+0.87{ V } _{ 2 }$
                        $\boxed { \dfrac { { V } _{ 1 } }{ { V } _{ 2 } } =\dfrac { 3 }{ 10 }  } $

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 70 g substance has a volume of $35:cm^3$. It will float on the surface of the water.

physics upthrust in fluids, archimedes' principle and floatation experimental verification of archimedes' principle archimedes' principle archimedes' principle and its applications

  1. True

  2. False

Show answer
Correct Option: B
Explanation:

Given:
Mass of substance $= 70g$.
Volume of substance $= 35cm^3$
density of water $= 1gm^{-3}$
By using the formula,
Density $=\dfrac{Mass}{Volume}$
Density of sub stance $= \dfrac{70}{35}=2gm^{-3}$
since, the density of the substance is more than the density, the gravitational force acting on it will be stronger than the buoyant force of water acting it, it will sink and not float on the surface 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.