Tag: measurement of density

Questions Related to measurement of density

The heart of man pumps 5 litre of blood through the arteries per minute at a pressure of 150 mm of mercury. If the density of mercury. If the density of mercury be $13.6 \times 10^3 \ kg/m^3$ and g = 10 m/$s^2$ then the power of heart in watt is: 

chemistry substances in the surroundings - their states and properties measurement of density properties of substances fundamental and derived units

  1. $2.35$

  2. $3.0$

  3. $1.50$

  4. $1.70$

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Correct Option: D

State whether true or false.
An iron ball and a copper ball of same mass have the same volume.

chemistry substances in the surroundings - their states and properties measurement of density properties of substances fundamental and derived units

  1. True

  2. False

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Correct Option: B
Explanation:

Since copper and iron have different density, hence both balls will have different volumes for same mass.

A boat floating in a tank is carrying passenger. If the passangers drink water, how will its affect the water level of the tank?

chemistry substances in the surroundings - their states and properties measurement of density properties of substances fundamental and derived units

  1. It will go down

  2. It will rise

  3. It will remain unchanged

  4. It will depend on atmospheric pressure

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Correct Option: C
Explanation:

If passenger drinks water then the weight of boat get increase and the boat will displace the same amount of water in the tank resulting no net change in the water level.

Mass per unit volume is called ..... of a substance.

chemistry substances in the surroundings - their states and properties measurement of density properties of substances fundamental and derived units

  1. Specific Gravity

  2. Density

  3. Gravity

  4. None of these

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Correct Option: B
Explanation:

It is very well known that mass per unit volume is defined as density. 

Density of water is ___________?

chemistry substances in the surroundings - their states and properties measurement of density properties of substances fundamental and derived units

  1. $1000kg/m^3$

  2. $1kg/m^3$

  3. $1000g/cm^2$

  4. $100kg/m^3$

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Correct Option: A
Explanation:

Density of water is $1000kg/m^3$.

ρ (rho) = density, m = mass, V = volume. The SI unit of density is kg/m3. Water of 4 °C is the reference ρ = 1000 kg/m3 = 1 kg/dm3 = 1 kg/l or 1 g/cm3 = 1 g/ml.

A tank $2\ m$ high is half filled with water and then filled to the top with oil of density $0.80\ g/cc$. What is the pressure at the bottom of the tank due to these liquids (Take $g=10\ ms^{-2}$) is

chemistry substances in the surroundings - their states and properties measurement of density properties of substances fundamental and derived units

  1. $1.80\times 10^{3}\ Nm^{-2}$

  2. $0.9\times 10^{3}\ Nm^{-2}$

  3. $1.8\times 10^{4}\ Nm^{-2}$

  4. $0.9\times 10^{4}\ Nm^{-2}$

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Correct Option: C
Explanation:

Density of oil=0.80 g/cc=800 kg/m$^{3}$

Density of water=1 g/cc=1000 kg/m$^{3}$
Pressure of water=Height will be 1 m half filled
$\Longrightarrow hdg=1 m \times 1000 kg/m^{3} \times 10m/s^{2}=10000 Pa$
Pressure by oil$=hdg$
Total pressure$=(1 \times 8000 \times 10)=8000 Pa+10000 Pa = 18000 Pa=1.8 \times 10^{4} N/m^{2}$

Density of ice is $\sigma$ and that of water is $\rho$. What will be the decrease in volume when a mass $M$ of ice melts 

chemistry substances in the surroundings - their states and properties measurement of density properties of substances fundamental and derived units

  1. $\dfrac {M}{\sigma - \rho}$

  2. $\dfrac {\sigma - \rho}{M}$

  3. $M\left [\dfrac {1}{\sigma} - \dfrac {1}{\rho}\right ]$

  4. $M\left [\dfrac {1}{\rho} - \dfrac {1}{\sigma}\right ]$

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Correct Option: D
Explanation:

Volume of ice= Mass/Density= $M/P$

Volume of water= Mass/Density= $M/\sigma$
Decrease in volume= $V _i-V _w$
$=\cfrac {M}{P}-\cfrac {M}{\sigma}= M\left[\cfrac {1}{P}-\cfrac {1}{\sigma}\right]$

By sucking through a straw, a boy can reduce the pressure in his lungs to $750\ mm$ of $Hg$ (density$ = 13.6\,\,g/c{m^3}$). Using a straw, he can drink water from a maximum depth of

chemistry substances in the surroundings - their states and properties measurement of density properties of substances fundamental and derived units

  1. $13.6\ cm$

  2. $1.36\ cm$

  3. $0.136\ cm$

  4. $10\ cm$

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Correct Option: A
Explanation:

Given Pressure in lungs${P} _{lungs}=750$ mm of Hg

and atmospheric pressure${P} _{atm}=760$ mm of Hg
Now pressure difference $\Delta{P}=760-750=10$ mm of Hg=1 cm of Hg
Now
1 cm of Hg$={\rho} _{water}gh$
$1{\rho} _{Hg}g={\rho} _{water}gh$
$13.6g=gh$
$h=13.6 cm$

Maximum density of $H _2O$is at the temperature

chemistry substances in the surroundings - their states and properties measurement of density properties of substances fundamental and derived units

  1. $32^oF$

  2. $39.2^oF$

  3. $42^oF$

  4. $4^oF$

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Correct Option: B
Explanation:

Maximum density of water is at $4^0C$


Here, the value in degree celsius is converting to degree Fahrenheit.

$T(°F) = (T(°C) × \dfrac 95 )+ 32$

or

$T(°F) = (T(°C) × 1.8) + 32$

We have,

$T(^0C)=4^0C$

Then,

$T(°F) = (4 × 1.8) + 32=39.2^oF$

A body of density ${d _1}$ is counterpoised by $Mg$ of weights of density ${d _2}$ in air of density $d.$ Then the true mass of the body is

chemistry substances in the surroundings - their states and properties measurement of density properties of substances fundamental and derived units

  1. $M$

  2. $M\left( {1-\dfrac{d}{{{d _2}}}} \right)$

  3. $M\left( {1 - \dfrac{d}{{{d _1}}}} \right)$

  4. $\dfrac{{M\left( {1 - d/{d _1}} \right)}}{{\left( {1 - d/{d _2}} \right)}}$

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Correct Option: D