Q 31 :

A gas of certain mass filled in a closed cylinder at a pressure of 3.23 kPa has temperature 50 °C. The gas is now heated to double its temperature. The modified pressure is ____ Pa.               [2026]

Q 32 :

The mean free path of a molecule of diameter $5\times {10}^{-10} \text{m}$ at the temperature $41°\text{C}$ and pressure $1.38\times {10}^5 \text{Pa}$ is given as ______ m.

(Given $k_B=1.38\times {10}^{-23} \text{J/K}$)    [2026]

• $10\sqrt{2}\times {10}^{-8}$

   

• $2\sqrt{2}\times {10}^{-8}$

   

• $2\times {10}^{-8}$

   

• $2\sqrt{2}\times {10}^{-10}$

   

Q 33 :

An air bubble of volume $2.9 cm³$ rises from the bottom of a swimming pool of 5 m deep. At the bottom of the pool water temperature is 17 $°C$. The volume of the bubble when it reaches the surface, where the water temperature is 27 $°C$, is ____ $cm³.$
(g = 10 $m/s²$, density of water = $10³ kg/m³$,  and 1 atm pressure is $10⁵$ Pa)   [2026]

• 2.0

   

• 4.2

   

• 3.0

   

• 4.5

   

Q 34 :

The r.m.s. speed of oxygen molecules at $47°\text{C}$ is equal to that of the hydrogen molecules kept at ______ $°\text{C.}$

(Mass of oxygen molecule / mass of hydrogen molecule = 32/2)     [2026]

• −235

   

• −253

   

• −20

   

• −100