Answer:
[tex]\dfrac{h_2}{h_1}=\dfrac{1}{2}[/tex]
Explanation:
Lets take h is height of cylinder immersed in the water
We know that for floating body
[tex]h=\dfrac{\rho_cL}{\rho_l}[/tex]
Where [tex]\rho_c[/tex] density of cylinder
[tex]\rho_l[/tex] density of water
For both cylinder fluid is same also density of cylinders are also same
So
[tex]\dfrac{h_1}{L_1}=\dfrac{h_2}{L_2}[/tex]
[tex]\dfrac{h_1}{h_2}=\dfrac{L_1}{L_2}[/tex]
[tex]\dfrac{h_1}{h_2}=\dfrac{20}{10}[/tex]
[tex]\dfrac{h_2}{h_1}=\dfrac{1}{2}[/tex]