Question
An equation is given as $$\left( {p + \frac{a}{{{V^2}}}} \right) = b\frac{\theta }{V},$$ where $$p =$$ pressure, $$V =$$ volume and $$\theta =$$ absolute temperature. If $$a$$ and $$b$$ are constants, then dimensions of $$a$$ will be
A.
$$\left[ {M{L^5}{T^{ - 2}}} \right]$$
B.
$$\left[ {{M^{ - 1}}{L^5}{T^2}} \right]$$
C.
$$\left[ {M{L^{ - 5}}{T^{ - 1}}} \right]$$
D.
$$\left[ {M{L^5}T} \right]$$
Answer :
$$\left[ {M{L^5}{T^{ - 2}}} \right]$$
Solution :
From principle of homogeneity of dimensions. Dimensions of $$p =$$ dimensions of $$\frac{a}{{{V^2}}}$$
$$\eqalign{
& p = \frac{a}{{{V^2}}} \Rightarrow a = p{V^2} \cr
& = \left[ {M{L^{ - 1}}{T^{ - 2}}} \right]{\left[ {{L^3}} \right]^2} \cr
& = \left[ {M{L^5}{T^{ - 2}}} \right] \cr} $$