Question

A beaker with a liquid of density 1.4 g cm⁻³ is in balance
over one pan of a weighing machine. If a solid of mass 10 g
and density 8 g cm⁻³ is now hung from the top of that pan
with a thread and sinking fully in the liquid without touching
the bottom, the extra weight to be put on the other pan for
balance will be
(a) 10.0 g
(b) 8.25 g
(c) 11.75 g
(d) –1.75 g

Answer 1

Answer:

The the extra weight to be put on the other pan for balance will be 1.75g

Density of the liquid = 1.4g (Given)

Mass = m = 10g (Given)

Density of the mass = 8g (Given)

Volume of the solid mass = Mass of solid / Density of solid

= 10/8

= 5/4

Thus, volume is 5/4 g/cm³

Volume of the liquid = 5/4 ( as the solid will displace the liquid in its own volume)

Mass of the liquid = Volume × density of liquid displaced

= 5/4 × 1.4

= 1.75g

Thus, the extra weight needed is 1.75g.