Question

Two wooden blocks A and B float in a liquid of density ${\rho }_L$ as shown. The distance L and H are shown. After some time, block B falls into the liquid, so that L decreases and H increases. If density of block B is ${\rho }_B$, find the correct option

• A. ${\rho }_L={\rho }_B$
• B. ${\rho }_L>{\rho }_B$
• C. ${\rho }_L<{\rho }_B$
• D. unpredictable

Answer 1

Answer: (B)

${\rho }_L>{\rho }_B$

In the first situation, when B is placed over A weight of B = ${\rho }_{B}Vg$

When it falls down in water,

Apparent loss in weight = weight in air - weight in water

= ${\rho }_{B}Vg-{\rho }_{L}Vg$

Since, according to the given condition, H increases and L decreases, therefore this apparent loss in weight should be negative.

Therefore, ${\rho }_B<{\rho }_L$