Question

A solid weighs 15 gm in air and 13 gm when completely immersed in a liquid of relative density 0.8 find the volume of solid

Answer 1

Volume of Solid is 2.5 $cm^3$

Explanation:

Given, weight of solid in air = 15 gf and weight of solid in liquid = 13 gf.,  

• Relative Density of liquid = 0.8

Therefore, Density of liquid = 0.8 g $cm^3$

(i) Let V be the volume of the solid.

Weight of liquid displaced = Volume of liquid displaced $\times$ density of liquid $\times$ g

                                         = V $\times$ 0.8g dyne

                                        = V $\times$ 0.8 gf

Loss in the weight of the solid when immersed in the liquid = 15 - 13 = 2 gf

But the weight of liquid displaced is equal to the loss in weight of the solid when immersed in liquid.

Therefore, V $\times$ 0.8 = 2  

or V = $\frac {20}{0.8}$

V = $\frac {5}{2}$  $cm^3$

V = 2.5 $cm^3$

Answer 2

Answer:

2.5 cm^3

Explanation:

Relative density of liquid 0.8

Density of liquid 0.8

Let v be the volume

Wight of water displaced=density of water*volume of water*g

W=0.8*v

Wight of water displaced 15-13=2gm

2=0.8*v

V=2/0.8

V=2.5