Physics · Science General

Units and Measurement

1,044 Questions

Master the fundamentals of physics with these practice questions on units and measurement. The topics include fundamental SI units, derived quantities, and specific units for power, force, and light. These questions are essential for building a strong foundation for competitive exams.

SI fundamental unitsUnits of powerDerived quantities unitsThermal energy unitsVolume measurement unitsElectric current units

Units and Measurement Questions

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

The SI unit of density is __________.

  1. $ \displaystyle kg/m^{3} $
  2. $ \displaystyle kg/m^{2} $
  3. $ \displaystyle kg^{3} $
  4. $ \displaystyle m^{3} $
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Density of substance is mass per unit volume hence its unit are $kg/{ m }^{ 3 }$ in S/units & $gm/{ cm }^{ 3 }$ in CGS.

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

Mass per unit volume of a substance is called its density. True or false.

  1. True

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

Density of substance is a characterstic property of a substance defined as mass of substance per unit volume.

density = $\dfrac { mass\quad of\quad substance }{ volume\quad of\quad substance } $.

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

Define density.

  1. Density of a substance is defined as the weight per unit volume of that substance.

  2. Density of a substance is defined as the mass per unit volume of that substance.

  3. Density of a substance is defined as the volume per unit mass of that substance.

  4. Density of a substance is defined as mass times volume of the substance.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Density of a substance is defined as the mass per unit volume. Its SI unit is $kgm^{-3}$. For example, the density of water at room temperature and atmospheric pressure is $1\ kgm^{-3}$.

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

Which of the following is true about the density of a substance?

  1. It is a derived quantity.
  2. The unit of density in SI system is kilogram per metre$^3$.

  3. The density of a substance can be measured if the mass of the substance for a certain volume is known.

  4. Density is a vector quantity
Reveal answer Fill a bubble to check yourself
A,B,C Correct answer
Explanation

Let the mass of the substance be $m$ and its volume be $V$. Then the density of the substance is defined as the ratio of mass to the volume of the body.

Thus the density of a substance can be derived as  $\rho = \dfrac{m}{V}$

SI unit of mass is $kg$ and that of the volume is $m^3$. Thus SI unit of density is  $kg/m^3$.
The density of a substance is a scalar quantity, not a vector quantity as it has magnitude only.
Hence options A, B and C are correct.

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

SI unit of density is ________ times its CGS unit.

  1. 1000

  2. 10

  3. 0.1

  4. 0.001
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

SI unit of density $=\dfrac { kg }{ { m }^{ 3 } } =\dfrac { 1000 }{ 10^6 } \dfrac { g }{ cc } $

                             $\dfrac { 1kg }{ { m }^{ 3 } } ={ 10 }^{ -3 }9/cc$

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

Which of the following is true about the density of a substance?

  1. It is a derived quantity.
  2. The unit of density in SI system is kilogram per metre$^3$.

  3. The density of a substance can be measured if the mass of the substance for a certain volume is known.

  4. Density is a vector quantity.
Reveal answer Fill a bubble to check yourself
A,B,C Correct answer
Explanation

The density of a substance is defined as the mass of the substance per unit volume of the substance.
$\rho=\dfrac mV$

Its unit is $kg/m^3$

It is a derived quantity as it uses the unit of mass and the unit of length.
The unit of density in the SI system is kilogram per meter $^3$.
The density of a substance can be measured if the mass of the substance for a certain volume is known.

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

The density of mercury is $13600 kg m^{-3} $.Its  value in CGS system will be:

  1. $13.6 g cm^{-3}$
  2. $1360 g cm^{-3}$
  3. $136 g cm^{-3}$
  4. $1.36 g cm^{-3}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The $C.G.S.$ unit of kg is Gm$.$ and that of meter is cm$.$ When we convert $13600\,kg{m^{ - 3}}$ then $13600 \times 1000\left( {100 \times 100 \times 100} \right) = 13.6\,gc{m^{ - 3}}$

Hence,
option $(A)$ is correct answer.

Multiple choice bio-chemistry cell-the basic unit of life introduction to cell discovery and cell theory cell discovery cell discovery and cell theory cell as structural and functional unit

The unit of measurement used for expressing dimension (size) of cells is

  1. Centimeter

  2. Millimeter

  3. Micrometer

  4. Meter
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The majority of cells are small. Normal animal cell size varies from 10 to 30 micrometer, while plant cell stretches from 10 to 100 micron. 

Multiple choice chemistry metals physical properties of metals and non-metals some physical properties of metals general characteristics and uses of metals

The density of ice is $0.921\;g\ cm^{-3}$. Calculate the mass of a cubic block of ice which is $76\;mm$ on each side.

  1. $49 \:g$
  2. $4\times 10^2\;g$
  3. $0.04 \:g$
  4. $4\times 10^3\;g$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Now, 1 $mm $ =   0.1 $cm$

$ \therefore $ 76$mm $ =   7.6 $cm$
Volume of cube $ =  $ $ (7.6)^3$ $ =  $ 438. 98 $ cm^3$
Now, mass $ =  $ density $ \times $ volume $ =  $ 0.921 $ \times $ 438.98 $ =  $ 404 $g$ $ =  $ $ 4.04 \times10^2 :g$