Q 11-12-116JEE MainJEE Main 2021 (27 Aug, Shift 1)Medium
A balloon carries a total load of $185$ kg at normal pressure and temperature of $27^\circ$C. What load will the balloon carry on rising to a height at which the barometric pressure is $45$ cm of Hg and the temperature is $-7^\circ$C. Assuming the volume constant?
Answer: (B) $123.54$ kg
At constant volume, the load the balloon can carry is proportional to the density of the surrounding air, $\rho \propto \dfrac{P}{T}$.
$$W_2 = 185\times\frac{45}{76}\times\frac{300}{266} \approx 123.54\ \text{kg}$$
Solution by Sreeraj P, M.Sc Physics