A famous relation in physics relates 'moving mass' $m$ to the 'rest mass' $m_{0}$ of a particle in terms of its speed $v$ and the speed of light, $c .$ (This relation first arose as a consequence of special relativity due to Albert Einstein). A boy recalls the relation almost correctly but forgets where to put the constant $c$. He writes:
$m=\frac{m_{0}}{\left(1-v^{2}\right)^{1 / 2}}$
Guess where to put the missing $c$
A famous relation in physics relates 'moving mass' $m$ to the 'rest mass' $m_{0}$ of a particle in terms of its speed $v$ and the speed of light, $c .$ (This relation first arose as a consequence of special relativity due to Albert Einstein). A boy recalls the relation almost correctly but forgets where to put the constant $c$. He writes:
$m=\frac{m_{0}}{\left(1-v^{2}\right)^{1 / 2}}$
Guess where to put the missing $c$
Given the relation, $m=\frac{m_{0}}{\left(1-v^{2}\right)^{\frac{1}{2}}}$
Dimension of $m= M ^{1} L ^{0} T ^{0}$
Dimension of $m_{0}= M ^{1} L ^{0} T ^{0}$
Dimension of $v= M ^{0} L ^{1} T ^{-1}$
Dimension of $v^{2}= M ^{0} L ^{2} T ^{-2}$
Dimension of $c= M ^{0} L ^{1} T ^{-1}$
The given formula will be dimensionally correct only when the dimension of L.H.S is the same as that of R.H.S.
This is only possible when the factor, $\left(1-v^{2}\right)^{1 / 2}$ is dimensionless i.e., $\left(1-v^{2}\right)$ is dimensionless. This is only possible if $v^{2}$ is divided by $c^{2} .$
Hence, the correct relation is
$m=\frac{m_{0}}{\left(1-\frac{v^{2}}{c^{2}}\right)^{\frac{1}{2}}}$
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A dimensionless quantity is constructed in terms of electronic charge $e$, permittivity of free space $\varepsilon_0$, Planck's constant $h$, and speed of light $c$. If the dimensionless quantity is written as $e^\alpha \varepsilon_0^\beta h^7 c^5$ and $n$ is a non-zero integer, then $(\alpha, \beta, \gamma, \delta)$ is given by
A dimensionless quantity is constructed in terms of electronic charge $e$, permittivity of free space $\varepsilon_0$, Planck's constant $h$, and speed of light $c$. If the dimensionless quantity is written as $e^\alpha \varepsilon_0^\beta h^7 c^5$ and $n$ is a non-zero integer, then $(\alpha, \beta, \gamma, \delta)$ is given by
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convert $1\; newton$ ($SI$ unit of force) into $dyne$ ($CGS$ unit of force)
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Match List $I$ with List $II$ and select the correct answer using the codes given below the lists :
List $I$
List $II$
$P.$ Boltzmann constant
$1.$ $\left[ ML ^2 T ^{-1}\right]$
$Q.$ Coefficient of viscosity
$2.$ $\left[ ML ^{-1} T ^{-1}\right]$
$R.$ Planck constant
$3.$ $\left[ MLT ^{-3} K ^{-1}\right]$
$S.$ Thermal conductivity
$4.$ $\left[ ML ^2 T ^{-2} K ^{-1}\right]$
Codes: $ \quad \quad P \quad Q \quad R \quad S $
Match List $I$ with List $II$ and select the correct answer using the codes given below the lists :
| List $I$ | List $II$ |
| $P.$ Boltzmann constant | $1.$ $\left[ ML ^2 T ^{-1}\right]$ |
| $Q.$ Coefficient of viscosity | $2.$ $\left[ ML ^{-1} T ^{-1}\right]$ |
| $R.$ Planck constant | $3.$ $\left[ MLT ^{-3} K ^{-1}\right]$ |
| $S.$ Thermal conductivity | $4.$ $\left[ ML ^2 T ^{-2} K ^{-1}\right]$ |
Codes: $ \quad \quad P \quad Q \quad R \quad S $
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