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 intensity and loudness waves physics

Decibel is the unit of physical quantity used for : 

  1. The speed of light

  2. The intensity of heat

  3. The intensity of sound

  4. The frequency of radiowaves
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Answer is C.

The intensity or loudness of a sound depends upon the extent to which the sounding body vibrates, i.e., the amplitude of vibration. A sound is louder as the amplitude of vibration is greater, and the intensity decreases as the distance from the source increases. Loudness or intensity of sound is measured in units called decibels. 

Multiple choice intensity and loudness waves physics

S. I. unit of intensity of sound is:

  1. joule s$^{-1}$ m$^{-2}$
  2. watt m$^{-2}$
  3. joule s/m$^2$

  4. both A and B
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In S. I. unit of intensity of sound is
joule s$^{-1}$ m$^{-2}$ or watt m$^{-2}$
Intensity = sound energy/time $\times$ area

Multiple choice introduction to induction electromagnetic induction electromagnetic induction and alternating currents physics

The unit of inductance is equivalent to

  1. $\dfrac {volt\times ampere}{second}$
  2. $\dfrac { ampere}{volt\times second}$
  3. $\dfrac {volt}{Ampere\times second}$
  4. $\dfrac {volt\times second}{ampere}$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

$As \, \varepsilon \, = \,  L \, \dfrac{dI}{dt},$
$L \, = \, \varepsilon \dfrac{dt}{dI} \Rightarrow \, L \, = \, \dfrac{volt \times second}{ampere}$

Multiple choice introduction to induction electromagnetic induction electromagnetic induction and alternating currents physics

Henry, the SI unit of inductance can be written as :

  1. weber ampere$^{-1}$
  2. volt second ampere$^{-1}$
  3. joule ampere$^{-1}$
  4. ohm s$^{-1}$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The SI unit of inductance is Henry,
$\displaystyle L =-\dfrac{e}{\dfrac{di}{dt}}$
SI unit $= \displaystyle \dfrac{volt}{A} \times s$
$=volt \times second \times  ampere^{-1}$

Multiple choice introduction to induction electromagnetic induction electromagnetic induction and alternating currents physics

Multiple Correct Answers Type
The SI unit of inductance, henry, can be written as

  1. Weber/ampere

  2. Volt-second / ampere
  3. $Joule / (ampere)^2$

  4. Ohm-second
Reveal answer Fill a bubble to check yourself
A,B,C,D Correct answer
Explanation

$L=\cfrac{\phi}{i}$

$L=\cfrac{weber}{Ampere}$
$V=L\cfrac{Ldi}{dt}$
$L\to$ volt.second/ampere
$E=\cfrac{1}{2}Li^2$
$L\to $joule/(ampere$)^2$
$\omega L=X _L$
$L\to$ohm.second
Hence all are correct.

Multiple choice introduction to induction electromagnetic induction electromagnetic induction and alternating currents physics

The SI unit of inductance, the henry, can be written as :

  1. weber / ampere

  2. volt second / ampere
  3. joule / ampere$^2$

  4. ohm second
Reveal answer Fill a bubble to check yourself
A,B,C,D Correct answer
Explanation

$ L\dfrac{dI}{dt} = emf = \dfrac{d\phi}{dt}$


a) $ [L] = weber / ampere $

b) $ [L] = volt.second / ampere $

c) $ Joule = volt \times ampere \times second $

$ \Rightarrow volt \times second = Joule / ampere$

$ \Rightarrow [L] = joule/ ampere^2$

d) $ V = IR \Rightarrow volt = ampere.ohm$

$\Rightarrow [L] = ohm.second$.

Multiple choice introduction to induction electromagnetic induction electromagnetic induction and alternating currents physics

Which of the following units denotes the dimensions ${M}{L}^{2}/{Q}^{2}$, where ${Q}$ denotes the electric charge?

  1. $Weber$ ($Wb$)
  2. $Wb$$/\mathrm{m}^{2}$
  3. $Henry$ ($H$)
  4. $\mathrm{H}/\mathrm{m}^{2}$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Weber $=ML^2T^{-2}I^{-1}$
$=ML^2T^{-2}Q^{-1}T=ML^2T^{-1}Q^{-1}$   ($I=QT^{-1}$)
Henry H is  SI unit of inductance. 
$H=ML^2T^{-2}I^{-2}$     also $I=QT^{-1}$
so $H=ML^2T^{-2}Q^{-2}T^2=ML^2Q^{-2}$

Multiple choice evs weather, climate and adaptation of animals to different climates climate and weather weather, climate and adaptations of animals to climate atmosphere and its components

The unit of pressure most commonly found on a surface weather map is:

  1. Inches of mercury (Hg)

  2. Millibars or hectopascals

  3. Pounds per square inch

  4. Millimeters of mercury (Hg)
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Meteorologists use millibars (mb) or hectopascals (hPa) as the standard units for atmospheric pressure on surface weather maps. These units are preferred for their consistency in scientific calculations.