What is Poisson’s ratio? Why does it have no unit?

Why strain has no unit?

What is radius ratio ? How does it help to predict the structure of ionic compounds ?

What is solubility product? Why does the solubility product expression does not contain the concentration term of undissolved solid?

Why does moon have no atmosphere?

A material has Poisson 's ratio 0.50 . If a uniform rod it suffers a longitudinal strain of 2 xx 10 ^(-3) then the percentage change in volume is

Check that the ratio (ke^2)/(Gm_em_p) is dimensionless. Look up a Table of Physical Constants and determine the value of this ratio. What does the ratio signify ?

Write down the dimension of Poisson's ratio with respect to M,L and T.