Number of particles is given by $n=-D\cfrac { { n }_{ 2 }-{ n }_{ 1 } }{ { x }_{ 2 }-{ x }_{ 2 } }$ crossing a unit area perpendicular to X-axis in unit time, where ${ n }_{ 1 }$ and ${ n }_{ 2 }$ are number of particles per unit volume for the value of $x$ meant to ${x}_{2}$ and ${x}_{1}$. Find dimensions of $D$ called as diffusion constant :

The frequency of vibration of the string is given by

$v=\dfrac {p}{2l}\left [ \dfrac {F}{m} \right ]^{1/2}$

Here, p is the number of segments in the string and l is the length. The dimensional formula for m will be

নিচের কোনটি দুরত্বের একক নয়?  

$\left ( P + \frac{a}{V^{2}} \right ) \left ( V - b \right ) = R T$   সমীকরণটিতে a এর মাত্রা কত?

The Van der Waal's equation of state for some gases can be expressed as:

$(P + \dfrac{a}{V^2})(V - b) = RT$

where P is the pressure, V is the molar volume, and T is the absolute temperature of the given sample of gas and a,b and R are constants.

The dimensions of a are