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 physics dynamics - explaining motion exponentiation index notation and products of prime factors powers

If the units of length and force are increased four times, then unit of energy will

  1. becomes 8 times

  2. becomes 16 times

  3. decrease 16 times

  4. increase 4 times
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Unit of Energy $= kg. m^2/ s^2$

Unit of Force $= kg. m/s^2$

Unit of Length $= m$

Thus, unit of energy in terms of unit of force and length is given by

Unit of Energy $= (kg. m/s^2) \times (m)$

If the units of length and force are increased by four times,

the unit of energy will be:

Unit of Energy $= (4 .kg. m/s^2) \times (4m)$

Unit of Energy $= 16 (kg. m^2/s^2)$

Therefore, if the units of length and force are increased by four times, the unit of energy will change by $16$ times.

Multiple choice physics dynamics - explaining motion exponentiation index notation and products of prime factors powers

If 1 mg $ns^{-1}$ = $10^x \mu g ps^{-1}$, then the value of x is _________.

  1. 1

  2. 2

  3. -1

  4. 0
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
We know that
$1\ mg=10^3\ \mu g$
$1\ ns=10^3\ ps$

Therefore, it can be written as:
$1mgn{ s }^{ -1 }={ 10 }^{ 3 }\mu gn{ s }^{ -1 }$

$ =\dfrac { { 10 }^{ 3 } }{ { 10 }^{ 3 } } \mu gp{ s }^{ -1 }$

$ ={ 10 }^{ 0 }\mu gp{ s }^{ -1 }\\ \Rightarrow x=0$
Multiple choice physics work and energy commercial unit of energy power work and power

Choose the correct option.

  1. kW$=$ unit of power and kWh $=$ unit of energy.
  2. kW$=$ unit of energy and kWh $=$ unit of power.

  3. kW and kWh are both of unit of energy.

  4. kW and kWh are both of unit of power.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Electrical Power is measured in watts (W), kilo-watts (kW), mega-watts (MW), and giga-watts (GW). The power of a load can change quickly, especially if the load is turning on and off.

Electrical Energy is measured in kilowatt-hours (kWh), megawatt-hours, and sometimes (less commonly) in watt-hours or watt-seconds. Energy is the primary measurement used by the utility company to determine your bill each month (although demand and power factor are also sometimes used). Unlike power, energy does not change quickly, but instead accumulates gradually.

Multiple choice physics work and energy commercial unit of energy power work and power

Which of the following can be used to express energy? Symbols have their usual meanings for the units of physical quantities.
(i) Wh   (ii) VC    (iii) VAs$^2$  (iv)  A$^2\Omega$s

  1. (i) , (ii)

  2. (ii), (iii), (iv)

  3. (i), (ii), (iv)

  4. (i), (ii), (iii), (iv)
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Using   $E = Pt$       $\implies$ Energy can be expressed in $Wh$

Using  $W = qV$     $\implies$ Energy can be expressed in $VC$
Using  $H = i^2Rt$  $\implies$ Energy can be expressed in $A^2\Omega s$
Whereas  Energy cannot be expressed by  $VAs^2$
Hence option C is correct.

Multiple choice physics work and energy commercial unit of energy power work and power

Smallest commercial unit of energy is

  1. Kilowatt hour

  2. Watt second

  3. Watt hour

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

Smallest commercial unit of energy is called Watt hour. It is defined as the amount of electric energy, which flows through a conductor in one hour, at a power of one watt.

Multiple choice physics work and energy commercial unit of energy power work and power

Kilowatt-hour is the unit of :

  1. potential difference.

  2. electric power.

  3. electrical energy.

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

The kilowatt-hour (symbolized kWh) is a unit of energy equivalent to one kilowatt (1 kW) of power expended for one hour. The kilowatt-hour is commercially used as a billing unit for energy delivered to consumers by electric utilities.

Multiple choice chemistry materials around us and different types of houses materials around us matter and its states different states of matter

 Mass per unit volume can be defined as:

  1. volume

  2. weight

  3. density

  4. matter

  5. none of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Mass per unit volume can be defined as density. For example : when 1 g of water has volume of 1 mL, the density of water will be 1 g/mL.
Density $\displaystyle = \dfrac {\text {mass}}{\text {volume}}$

Multiple choice physics learning how to measure measurement of area and volume measurement of volume measurement of area, volume and density

Which is the correct form of expressing SI unit of volume?

  1. $\displaystyle { m }^{ 3 }$
  2. $cubicmetre$
  3. $\displaystyle { metre }^{ 3 }$

  4. all of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

SI unit of volume is $m^3$ which can also be written as $cubicmetre$ and $metre^3$. It is a big unit, the smaller units are also in use.

Multiple choice physics learning how to measure measurement of area and volume measurement of volume measurement of area, volume and density

Name the unit in which the volume of liquid is generally measured. How can this unit is related to L.

  1. kilogram, 1 litre = 10$^{-6}$ m$^3$
  2. litre, 1 litre = 10$^{-6}$ m$^3$
  3. litre, 1 litre = 10$^{-3}$ m$^3$
  4. litre, 1 litre = 10$^{-3}$ cm$^3$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Volume is generally measured in liter, $1\ liter=10^{-3}m^3$