Tag: measurements and units

Quizzes (10) Questions (257)

Questions Related to measurements and units

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

The unit of permittivity of free space, $ \varepsilon _ o $ is

  1. $\dfrac {Coulomb} {newton - meter}$
  2. $ \dfrac {newton - meter^2} { Coulomb ^2} $
  3. $\dfrac {Coulomb^2}{newton- meter^2} $
  4. $ \dfrac {Coulomb^2} {(newton-metre)^2}$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

From Coulomb's law, F = (1 / (4 pi epsilon_0)) * (q1 * q2 / r^2). Rearranging for epsilon_0 gives units of (Coulomb * Coulomb) / (newton * meter^2), which simplifies to Coulomb^2 / (newton * meter^2).

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

In the eqn. $\left (P+\dfrac {a}{V^2}\right )(V-b)=$ constant, the unit of $a$ is

  1. $dyne\times cm^5$
  2. $dyne\times cm^4$
  3. $dyne/cm^3$
  4. $dyne\times cm^2$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Units of both $P $ and $ \dfrac {a}{V^2}$ must be same.
So, $\dfrac {a}{V^2}=P$  $\implies   a=PV^2$ 

Since unit of $P$ is $dyne \ cm^{-2}$ and that of $V$ is $cm^3$.
$\therefore$ Unit of a is  $\dfrac {dyne}{cm^2}(cm^3)^2=dyne\times cm^4$

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

Which of the following physical quantity is different form others ?

  1. Displacement

  2. Velocity

  3. Force

  4. Kinetic energy
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Displacement, force, and velocity are vector quantities as they require direction as well as the magnitude for their representation but the kinetic energy is a scalar quantity as it does not require direction for its representation.

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 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.