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Question-52992




Question Number 52992 by prakash jain last updated on 16/Jan/19
Commented by prakash jain last updated on 16/Jan/19
Correct answer is ((4−R)/(2R)), NTA has given  ((4+R)/(2R)). This question is also from  9th Jan morning JEE main exam.
$$\mathrm{Correct}\:\mathrm{answer}\:\mathrm{is}\:\frac{\mathrm{4}−\mathrm{R}}{\mathrm{2R}},\:\mathrm{NTA}\:\mathrm{has}\:\mathrm{given} \\ $$$$\frac{\mathrm{4}+\mathrm{R}}{\mathrm{2R}}.\:\mathrm{This}\:\mathrm{question}\:\mathrm{is}\:\mathrm{also}\:\mathrm{from} \\ $$$$\mathrm{9th}\:\mathrm{Jan}\:\mathrm{morning}\:\mathrm{JE}{E}\:\mathrm{main}\:\mathrm{exam}. \\ $$
Answered by tanmay.chaudhury50@gmail.com last updated on 16/Jan/19
P_A =N_A (((RT)/V))  P_B =N_B (((RT)/V))  P=P_A +P_B =((RT)/V)(N_A +N_B )  N_A +N_B =((PV)/(RT))  N_B =((PV)/(RT))−N_A   N_B =((200×10)/(R×1000))−0.5  N_B =(2/R)−(1/2)  N_B =((4−R)/(2R))
$${P}_{{A}} ={N}_{{A}} \left(\frac{{RT}}{{V}}\right) \\ $$$${P}_{{B}} ={N}_{{B}} \left(\frac{{RT}}{{V}}\right) \\ $$$${P}={P}_{{A}} +{P}_{{B}} =\frac{{RT}}{{V}}\left({N}_{{A}} +{N}_{{B}} \right) \\ $$$${N}_{{A}} +{N}_{{B}} =\frac{{PV}}{{RT}} \\ $$$${N}_{{B}} =\frac{{PV}}{{RT}}−{N}_{{A}} \\ $$$${N}_{{B}} =\frac{\mathrm{200}×\mathrm{10}}{{R}×\mathrm{1000}}−\mathrm{0}.\mathrm{5} \\ $$$${N}_{{B}} =\frac{\mathrm{2}}{{R}}−\frac{\mathrm{1}}{\mathrm{2}} \\ $$$${N}_{{B}} =\frac{\mathrm{4}−{R}}{\mathrm{2}{R}} \\ $$
Answered by afachri last updated on 16/Jan/19
Answered by FelipeLz last updated on 26/Oct/21
PV = nRT  2.10^2 ∙10 = ((1/2)+x)∙R∙10^3   2 = ((1/2)+x)∙R  2 = ((1/2)+x)∙R  (2/R) = (1/2)+x  x = (2/R)−(1/2)  x = ((4−R)/(2R))
$${PV}\:=\:{nRT} \\ $$$$\mathrm{2}.\mathrm{10}^{\mathrm{2}} \centerdot\mathrm{10}\:=\:\left(\frac{\mathrm{1}}{\mathrm{2}}+{x}\right)\centerdot{R}\centerdot\mathrm{10}^{\mathrm{3}} \\ $$$$\mathrm{2}\:=\:\left(\frac{\mathrm{1}}{\mathrm{2}}+{x}\right)\centerdot{R} \\ $$$$\mathrm{2}\:=\:\left(\frac{\mathrm{1}}{\mathrm{2}}+{x}\right)\centerdot{R} \\ $$$$\frac{\mathrm{2}}{{R}}\:=\:\frac{\mathrm{1}}{\mathrm{2}}+{x} \\ $$$${x}\:=\:\frac{\mathrm{2}}{{R}}−\frac{\mathrm{1}}{\mathrm{2}} \\ $$$${x}\:=\:\frac{\mathrm{4}−{R}}{\mathrm{2}{R}} \\ $$

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