Physics · Science General

Units and Measurement

998 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 physics measurements and units kinds of units fundamental quantities standardized measurement

Unit of self inductance is

  1. $\cfrac { newton\ second }{ coulomb\quad \times \quad ampere } $
  2. $\cfrac { joule/coubmb\quad \times \quad second }{ ampere } $
  3. $\cfrac { volt\quad \times \quad metre }{ coulomb } $
  4. $\cfrac { newton\quad \times \quad metre }{ ampere } $
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Self inductance L has the SI unit Henry (H), which equals volt-second/ampere. From V = L(dI/dt), dimensionally [H] = [V][T]/[A]. Option B: joule×second/(coulomb×ampere) = (V×C×T)/(C×A) = V×T/A = Henry, which is correct. Note that 'coubmb' in option B appears to be a typo for coulomb.

Multiple choice physics measurements and units kinds of units fundamental quantities standardized measurement

kilowatt-hour is the unit of ____. 

  1. potential difference

  2. electric power

  3. electric energy

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

$\text{Kilowatt hour}$ is the $commercial$ unit of $electrical$ ENERGY.

As the power$(means $ $ \dfrac{Work}{time}=\dfrac{energy}{time})$
so $energy=power\times time $

$\text{so unit of energy= unit of power *unit of time =watt *second }$
Kilowatt-hour is just $3600\times 1000$ times  of the above value of energy.

Multiple choice physics measurements and units kinds of units fundamental quantities standardized measurement

Write the SI unit of the physical quantity having following dimensional formula
$\displaystyle [{ M }^{ 0 }{ L }^{ 2 }{ T }^{ -2 }{ K }^{ -1 }]$.

  1. $\displaystyle {m} { kg }^{ 2 }{ K }^{ -1 }$
  2. $\displaystyle {m} ^{2} { kg }^{ 2 }{ T }^{ -1 }$
  3. $\displaystyle {m} ^{2} { s }^{ -2 }{ K }^{ -1 }$
  4. $\displaystyle {m} ^{2} { kg }^{ 2 }{ K }^{ -1 }$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
SI unit of $M$ is $kg$, that of $L$ is $m$, $T$ is $s$ and temperature (K) is $K$.

So, SI unit of $[M^0L^2T^{-2}K^{-1}]$ is  $m^2s^{-2}K^{-1}$.
Multiple choice physics measurement of physical quantities kinds of units fundamental quantities standardized measurement

A dimensionless quantity

  1. never has a unit

  2. always has unit

  3. may have a unit

  4. does not exit
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A dimensionless quantity is that is always independent of basic $7$ units:-meter, second, kilogram, Kelvin, Candela, ampere.

But it is not necessary. A dimensionless quantity is unitless. And eg, for this, is radian (unit of angle), which is dimensionless quantity because it is the ratio of two lengths.

Multiple choice physics measurements and units kinds of units fundamental quantities standardized measurement

Some physical quantities are given in Column I and some possible SI units in which these quantities may be expressed are given in Column II. Match the physical quantities in Column I with the units in Column II.

Column I Column II
i. $GM _eM _s$ a. (volt) (coulomb) (metre)
ii. $3RT/M$ b. $(kilogram)(metre)^3 (second)^2$
iii. $F^2/q^2B^2$ c. $(meter)^2 (second)^{-2}$
iv. $GM _e/R _e$ d. $(farad) (volt)^2 (kg)^{-1}$


where G is universal gravitational constant; $M _e$ mass of the earth; $M _s$, mass of sun; $R _e$ radius of the earth; R, universal gas constant;T, absolute temperature; M, molar mass, F, force; q, charge; B, magnetic field.

  1. $i \rightarrow b., ii \rightarrow c.,d., iii \rightarrow c.,d., iv \rightarrow c.,d.,$
  2. $i \rightarrow a., ii \rightarrow c.,d., iii \rightarrow c.,d., iv \rightarrow c.,d.,$
  3. $i \rightarrow d., ii \rightarrow c.,d., iii \rightarrow c.,d., iv \rightarrow c.,d.,$
  4. $i \rightarrow c., ii \rightarrow c.,b., iii \rightarrow c.,d., iv \rightarrow c.,d.,$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

i. GM_eM_s is energy related (potential), ii. 3RT/M is velocity squared (m^2/s^2), iii. F^2/q^2B^2 is velocity squared, iv. GM_e/R_e is velocity squared. Matching these to the provided units leads to B.

Multiple choice physics energy and its forms idea of energy introduction to work and energy work and energy

Name the quantity which is measured in $Wh$.

  1. Force

  2. Power

  3. Energy

  4. All the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

We know that $ power = work/ time$.

Power has unit $W$ and time can have either seconds or minutes or hours.Hence work can have either $W\ min$ or $Wh$ or $Ws$. We in general consider work is nothing but energy. Hence energy can have unit $Wh$.