[tex]{\purple {\underline{\boxed{\sf{ Potential\: Energy \:=\: mgh}}}}}[/tex]
Where,
Now, Converting gram to kg
[tex]\longrightarrow\:[/tex] 1000g = 1kg
[tex]\longrightarrow\:[/tex] 20g = [tex]\sf\dfrac{20}{1000}[/tex]
[tex]\longrightarrow\:[/tex] = 0.02 kg
According to the question
[tex]\sf\red{Mass \:= \:0.02 kg}[/tex]
[tex]\sf\green{Gravitational \;force \:= \;10 m/s^{2}}[/tex]
[tex]\sf\purple{Height\: =\: 2 m}[/tex]
Putting these values
[tex]\to\:[/tex] Potential Energy = mgh
[tex]\to\:[/tex] Potential Energy = 0.02 × 10 × 2
[tex]\to\:[/tex] Potential Energy = 0.2 × 2
[tex]\to\:[/tex] Potential Energy = [tex]\bf\pink{0.4\:joules}[/tex]