BITSAT 2019 Slot 2 Solved Paper

Given, density of gas at point A,ρA=ρ0
General equation for an ideal gas
pV=nRT
⇒pV=

m

M

.RT[m→mass, M→ molecular mass ]
⇒p=

m

V

.

R

M

.T
⇒p=ρ(

R

M

)T‌‌‌[where, density ρ=

m

V

] .......(i)
Applying Eq. (i) at point A and B, respectively.
p=ρA(

R

M

)T0 ........(ii)
2p=ρB(

R

M

)3T0 ..........(iii)
From Eqs. (ii) and (iii), we get

1

2

=

ρA

ρB

.

1

3

⇒ρB=

2

3

ρA=

2

3

ρ0