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

The SI unit of thermal capacity is ;

  1. $J\ kg^{-1}\ K^{-1}$
  2. $J^{-1}\ kg\ K^{-1}$
  3. $JK^{-1}$
  4. $J\ kg\ K^{-1}$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation


The heat or thermal capacity of a defined system is the amount of heat required to raise the system's temperature by one degree. It is expressed in units of thermal energy per degree temperature.

$q= C\times t$

$C=\dfrac{q}{\triangle t}$

here,$C=$heat or thermal capacity
        $q=$heat required (J)
        $\triangle t={t} _{1}-{t} _{2}$ (K)

so,The S.I. unit of heat or thermal capacity is $J{K}^{-1}$

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

Column I gives three physical quantities. Select the appropriate units for these from the choices given in column II. Some of the physical quantities may have more than one choice.

Column-I Column - II
a) Capacitance d) Ohm second
b) Inductance e) Coulomb$^{2}$ joule$^{ -1 }$
c) Magnetic induction f) Coulomb volt$^{ -1 }$
g) Newton (ampere/metre)$^{ -1 }$
h) Volt second (ampere)$^{ -1 }$

  1. a-e,f; b-d,h; c-g

  2. a-h; b-d; c-e

  3. a-e; b-g,h; c-g

  4. a-e,f; b-d,h; c-d,e
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Capacitance is charge per unit volt. 

Volt has unit of work per unit chage. 
So capacitance has units of charge square per unit energy. 
Inductance is defined as volt per unit rate of change of current and voltage per unit current is resistance, so inductance is ohm second. 

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

The SI unit of magnetic permeability is

  1. ${ Am }^{ -1 }$
  2. ${ Am }^{ -2 }$
  3. ${ Hm }^{ -2 }$
  4. ${ Hm }^{ -1 }$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The correct option is D.

The magnetic permeability of any material is its property for allowing the magnetic line of force to pass through it. Therefore, the magnetic material can support the development of the magnetic field. This capability is measured by the magnetic permeability. Also, the magnetic line of force is directly proportional to the conductivity of the material. Its SI unit is Henry per meter i.e. $Hm^{-1}$ or newton per ampere square.

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

$\left( Coulomb \right) ^{ 2 }{ J }^{ -1 }$ can be the unit of :

  1. electric resistence

  2. electric energy

  3. electric capacity

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

Electric energy $=ML^{2}T^{-2}$
Electric power $=ML^{2}T^{-3}$
Electric resistance $= ML^{2}I^{-2}T^{-3}$
Electric capacity $=M^{-1}L^{-2}I^{2}T^{4}$$=\left ( \dfrac{I^{2}T^{2}}{(M^{1}L^{2}T^{-2})} \right )=\left ( \dfrac{Q^{2}}{J} \right )$
Hence, option C is correct.

Multiple choice physics measurement of physical quantities kinds of units fundamental quantities standardized measurement

The units which can neither derived from one another nor resolved into any thing more basic are called 

  1. Fundamental unit

  2. Scale

  3. Derived unit

  4. Standard unit
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The units which can neither derived from one another nor resolved into any thing more basic are called fundamental unit. It is independent of any other unit.

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

The Sl unit of length is the meter. Suppose we adopt a new unit of length which equals to $x$ meters. The area 1 $m ^ { 2 }$ expressed in terms of the new unit has a magnitude:

  1. $x$
  2. $x ^ { 2 }$
  3. $\dfrac { 1 } { x }$
  4. $\dfrac { 1 } { x ^ { 2 } }$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

SI unit of Length $=$ meters.

New Unit of Length $=x$ meters.

$1m=\dfrac 1x$ new units

SI unit of area : 

$A= 1m^2$   

$=1\times 1m^2$                        

$=\dfrac 1x\times \dfrac 1x $     

$=\dfrac{1}{x^2}$     

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

If $10 ^ { 7 }$ era is taken as unit of energy, $10 ^ { 5 }$ dyne as the unit of force, one second as unit of time. what is, the unit of length?

  1. $1$ $m$
  2. $10$ $m$
  3. $100$ $m$

  4. None
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Energy E = M L^2 T^-2 = 10^7 erg = 1 Joule. Force F = M L T^-2 = 10^5 dyne = 1 Newton. Time T = 1 second. Using F = M L T^-2 and E = F L, we get 1 Joule = 1 Newton * L, so L = 1 meter.

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

The MKS unit of quantity $\dfrac{\pi \eta r^4}{2}$ is :

  1. $N s {m}^{2} radian $
  2. $Ns/m/Radian$
  3. $Radian/Ns/m$
  4. $ Ns/m/Radian^2 $
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Unit of $\pi $ is radians.

Unit of $r$ is $m$.
Unit of coefficient of viscosity, $\eta =N\, s\, { m }^{ -2 } $
Whereas $2$ is just a number, so it is unit less.
Therefore, Unit of given expression $=radian \times$ $N\, s\, { m }^{ -2 }\times { m }^{ 4 }=N\,s \, { m }^{ 2 } \ radian$