If $x = a/t + b/t^2 + c$,where $x$ is the distance travelled by the body in metres and $t$ is the time in seconds,then the units of $b$ are:

The dimensional formula of $\mu_{0} \varepsilon_{0}$ is . . . . . . .

If ${\mu _0}$ and ${\varepsilon _0}$ denote the permeability and permittivity of free space,the dimensions of ${\mu _0}{\varepsilon _0}$ are:

In a relation $F = a \sin(k_1x) + b \sin(k_2t)$,where $F$,$x$,and $t$ denote force,distance,and time respectively. The units of $k_1$ and $k_2$ are respectively:

The density of a material in $SI$ units is $128 \ kg \ m^{-3}$. In a system of units where the unit of length is $25 \ cm$ and the unit of mass is $50 \ g$,the numerical value of the density of the material is:

The frequency of vibration of a string is given by $\nu = \frac{p}{2l} \left[ \frac{F}{m} \right]^{1/2}$. Here $p$ is the number of segments in the string,$l$ is the length,and $F$ is the tension. The dimensional formula for $m$ will be: