Physics MCQs for NEET — Practice Questions with Answers

rms velocity doesn't depend on pressure, it depends upon temperature only $ \nu_{rms} = \sqrt { 3RT \over Mo } \Rightarrow \nu_{rms} \alpha \sqrt T $ $ \therefore T \alpha \nu_{rms}^2 \Rightarrow { \nu_1 \over \nu_2 } = \sqrt { T_1 \over T_2 } $

$ \nu_{rms} = \sqrt { 3RT \over Mo } \Rightarrow \nu_1 \alpha \sqrt { 1 \over M_1 } and \nu_2 \alpha \sqrt { 1 \over M_2} \Rightarrow { \nu_1 \over \nu_2 } = \sqrt { M_2 \over M_1 } $

$ \nu_{rms} = \sqrt { 3RT \over Mo } \Rightarrow \nu_{rms} \alpha \sqrt T $ $ \therefore T \alpha \nu_{rms} ^2 $

$ \nu_{rms} = \sqrt { 3RT \over Mo } \Rightarrow T \alpha M_o $ (\nu_{rms} . R \rightarrow constant ) $

$ \nu_{rms} = \sqrt { 3RT \over Mo } \Rightarrow \nu _{rms} \alpha \sqrt { T \over Mo} $ $ \therefore { \nu_{He} \over \nu_{H_2}} ={ 5 \over 7} = \sqrt { T_{He} \times M_{H_2} \over T_{H2} M_{He} } \Rightarrow = { 25 \over 49 } \times {4 \over 2 } \times 273 $ $ \approx 273 K \approx 0 ^ \circ C$

$ \nu_{rms} = \sqrt { 3RT \over Mo } \Rightarrow M_o = { 3RT \over \nu_{rms} ^2 } = { 3 \times 8.3 \times 300 \over (1920)^2} = 2 \times 10^{-3} kg = 2g $ Gas is hydrogen

rms speed, $ \nu_{rms} = \sqrt { \nu_1^2 +\nu_2^2 + \nu_3^2 \over 3 }$ average speed .$ (\nu) = { \nu_1 +\nu_2 + \nu_3 \over 3 }$

$ { ( \nu_{rms} )_t \over ( \nu_{rms})_o} = \sqrt { T \over T_o} and rms speed increases by 10 \% $
$ \therefore 1.1 = \sqrt { 273 + t \over 273} or {273 + t \over 273 } = (1.1)^2 = 1.21 $ $ \therefore t = 273 ( 1.21 - 1 ) = 57.3 C$

$ \nu_{rms} \alpha \sqrt T $ $ \therefore { \nu_2 \over \nu_1} = \sqrt { T_2 \over T_1} $

$ \nu_{rms} = \sqrt { 3RT \over M_o} $ $ \% increase in \nu_{rms} = { \sqrt {3RT_2 \over M_o} - \sqrt{ 3RT_1 \over M_o } \over \sqrt { 3RT_1 \over M_o} } \times 100 \% = { 20 - 17.32 \over 17.32} \times 100 \% = 15.5 \% $