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 standardized measurement measurement of physical quantities need of unit for measurement measurements and experimentation physics

Which of the following does not has fundamental unit?

  1. Mass

  2. Time

  3. Force

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

The fundamental units are the units of the fundamental quantities, as defined by the International System of Units. They are not dependent upon any other units, and all other units are derived from them. There are seven basic fundamental quantities: Length, mass, time, electric current, amount of substance, luminous intensity & temperature. The quantities which are derived with the help of these basic physical quantities are called derived quantities. They are density, volume, pressure, force, etc.

Multiple choice standardized measurement measurement of physical quantities need of unit for measurement measurements and experimentation physics

The gravitational unit of force in the metric system is

  1. g wt

  2. N

  3. kg wt

  4. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Gravitational force is the force exerted by earth on any body which attracts to body towards earth. It is same as any other force.  The gravitational unit of force in the metric system is $kg\,wt$.

Multiple choice standardized measurement measurement of physical quantities need of unit for measurement measurements and experimentation physics

The unit of power is

  1. Joule per second only

  2. Joule only

  3. Joule per second and watt both

  4. Watt only

  5. Erg
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Power is defined as work divided by time, so its units are joules/second. Scientists have another name for this unit, too. It's the watt, named after James Watt, the Scottish inventor who helped develop the steam engine that powered the Industrial Revolution. In the SI system, the watt is defined as:


$1\,watt=1\,J/s=1\,kg\,m^2/s^3$

Multiple choice standardized measurement measurement of physical quantities need of unit for measurement measurements and experimentation physics

Which of the following pairs has not the same dimension?

  1. Stress; pressure

  2. Force; surface tension

  3. Impulse; linear momentum

  4. Frequency; angular velocity
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Surface Tension$ (T) =\dfrac{ Force}{Length}$  . . . . . (1)

Since, $Force = Mass \times Acceleration$

And, $Acceleration = \dfrac{velocity}{ time}= [L T^{-2}]$

$\therefore $ The dimensional formula of force $= M^1L^1T^{-2}$ . . . . (2)

On substituting equation (2) in equation (1) we get,

Surface Tension $(T) = \dfrac{Force}{  Length}$

Or, $T=\dfrac{[M^1L^1T^{-2}]}{[L^{1}]}=M^1T^{-2}$ 

Therefore, surface tension is dimensionally represented as $[M^1T^{-2}]$


Dimension of force $=M^1L^1T^{-2}$

So the dimension of force and surface tension are different.

Multiple choice evs how to save fuel fuels fuel and effects of burning fuel study of combustion

Fuel efficiency is measured as 

  1. Its calorific value

  2. Amount of heat produced by fuel per unit mass or volume
  3. $kJ/Kg$

  4. None of these
Reveal answer Fill a bubble to check yourself
A,B,C Correct answer
Explanation

Fuel efficieny can be measured as the amount of heat that is required by 1kg of fuel during combustion.  It is known as calorific value of the fuel.  The unit of measuring fuel efficieny is kJ/Kg.