Key Idea Compounds which have at least one double bond (C=C) and the groups attached with double bonded carbon atoms are different, exhibit geometrical isomerism. 
CH3CH2CH2CH2OH⇒ no geometrical isomers butanol CH3C≡CCH3⇒ no geometrical isomers CH3CH2C(OH)=CH2 ⇒ no geometrical isomers.