Question

A hollow sphere of inner radius $9$ cm and outer radius $10$ cm floats half submerged in a liquid of specific gravity $0.8$. The density of the material sphere is.

• A. $0.84g{cm}^{-3}$
• B. $1.48g{cm}^{-3}$
• C. $1.84g{cm}^{-3}$
• D. $1.24g{cm}^{-3}$

Answer 1

Answer: (B)

$1.48g{cm}^{-3}$

$Given:$ Inner radius$=9cm$ ;outer radius$=10cm$ ; specific gravity$=0.8$

$Solution:$ We know that,

$\frac{4}{3}\pi (1000r^3-729r^3)\rho$

$=\frac{2}{3}\pi 1000r^{3}0.8\rho \omega$

$271\rho =4\omega {\rho }_{\omega }$

$\rho =1.48{\rho }_{\omega }=1.48gm/{cm}^3$

$So,the$ $correct$ $option:B$