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QJEEM21Phdfe6: JEE Main 2021 Physics - Class 11 JEEM21Phdfe6 Solution: For an ideal gas the instantaneous change in pressure 'p' with…

For an ideal gas the instantaneous change in pressure 'p' with volume 'v' is given by the equation dpdv=−ap{{dp} \over {dv}} = - ap . If p = p0 at v =0 is the given boundary condition, then the maximum temperature one mole of gas can attain is : (Here R is the gas constant)

Multiple Choice Options

  • A p0aeR{{{p_0}} \over {aeR}}
  • B ap0eR{{a{p_0}} \over {eR}}
  • C infinity
  • D 0 ∘^\circ C

Step-by-Step Verified Solution

∫p0pdpP=−a∫0vdv\int\limits_{{p_0}}^p {{{dp} \over P} = - a\int\limits_0^v {dv} }

ln⁡(pp0)=−av\ln \left( {{p \over {{p_0}}}} \right) = - av

p=p0e−avp = {p_0}{e^{ - av}}

For temperature maximum p-v product should be maximum

T=pvnR=p0ve−avRT = {{pv} \over {nR}} = {{{p_0}v{e^{ - av}}} \over R}

dTdv=0⇒p0R{e−av+ve−av(−a)}{{dT} \over {dv}} = 0 \Rightarrow {{{p_0}} \over R}\{ {e^{ - av}} + v{e^{ - av}}( - a)\} = 0

p0e−avR{1−av}=0{{{p_0}{e^{ - av}}} \over R}\{ 1 - av\} = 0

v=1a,∞v = {1 \over a},\infty

T=p01Rae=p0RaeT = {{{p_0}1} \over {Rae}} = {{{p_0}} \over {Rae}}

at v = ∞\infty

T = 0

Option (a)

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