If the dimensions of a physical quantity are given by $\mathrm{M}^{\mathrm{a}} \mathrm{L}^{\mathrm{b}}…

If the dimensions of a physical quantity are given by $\mathrm{M}^{\mathrm{a}} \mathrm{L}^{\mathrm{b}} \mathrm{T}^c$, then the physical quantity will be
  1. pressure if $\mathrm{a}=1, \mathrm{~b}=-1, \mathrm{c}=-2$
  2. velocity if $a=1, b=0, c=-1$
  3. acceleration if a $=1, b=1, c=-2$
  4. force if $\mathrm{a}=0, \mathrm{~b}=-1, \mathrm{c}=-2$

Solution

(i) Dimensions of velocity $=\left[\mathrm{M}^0 \mathrm{~L}^1 \mathrm{~T}^{-1}\right]$ Here, $a=0, b=1, c=-1$ (ii) Dimensions of acceleration $=\left[\mathrm{M}^0 \mathrm{~L}^1 \mathrm{~T}^{-2}\right]$ Here, $\quad a=0, b=1, c=-2$ (iii) Dimensions of force $=\left[\mathrm{M}^1 \mathrm{~L}^1 \mathrm{~T}^{-2}\right]$ Here, $a=1, b=1, T=-2$ (iv) Dimensions of pressure $=\left[\mathrm{M}^1 \mathrm{~L}^{-1} \mathrm{~T}^{-2}\right]$ $\therefore$ Here, $\quad \mathrm{a}=1, \mathrm{~b}=-1, \mathrm{c}=-2$ $\therefore$ The physical quantity is pressure.

Asked in: NEET 2009 (Screening)

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