Answer:
Option A,B,D
Explanation:
(a) Total Internal energy
U=f12nRT+f22nRT
(Uave)permole=U2n
= 14[5RT+3RT]=2RT
(b) γmix=n1Cp1+n2Cp2n2Cv1+n2Cv2
=(1)7R2+(1)5R2(1)5R2+(1)3R2=32
Mmix=n1M1+n2M2n1+n2
M1+M22=2+42=3
speed of sound V=√γRTM
⇒ V∝√YM
VmixVHe=√γmixγHe×MHeMmix
= VmixVHe=√3/25/3×43=√65
(d) Vrms=√3RTM⇒Vrms∝1√M
VHeVH=√MHMHe=√24=1√2