What temperature the rms velocity of helium molecules will be equal to that of hydrogen molecule at NTP?

Get Instant Solutions

When in doubt download our app. Now available Google Play Store- Doubts App

25.

An ice box made of Styrofoam (thermal conductivity = 0.01 Jm-1s-1K) is used to keep liquids cool. It has a total wall area including lid of 0.8 m2 and wall thickness of 2.0 cm. A bottle of water is placed in the box and filled with ice. If the outside temperature is 30°C, the rate of flow of, heat into the box is (in Js-1)

C.

12

H = Qt = KAθ1 - θ2l = 0.01 × 0.8 (30 - 0)2 × 10-2                                         = 12 Js-1

Tardigrade - CET NEET JEE Exam App

© 2022 Tardigrade®. All rights reserved

Text Solution

844 k64 k`273^(@)c`273 k

Answer : C

Solution : The root mean square velocity , `v_" rms"sqrt((3RT)/(M))` <br> where , R is gas constant , T the absolute temperature ans M the molecular weight. <br> Given , `v_(He)=v_(H),T_(H)=273K` <br> `M_(H)=2,M_(He)=4` <br> `therefore" " (v_(H))/(v_(He))=sqrt((T_(H))/(T_(He))xx(M_(He))/(M_(H)))` <br> `1=sqrt((273)/(T_(He))xx(4)/(2))` <br> `rArr " " T_(He)=546K` <br> In `^.(@)C, T_(He)=(546-273)^(@)C=273^(@)C`