1.

A room of10 m xx 15m xx4m dimenstion having perfectly insulated walls, ceiling and floor has 60 students seated inside. The air inside the room is at 25^(@)C and 1 atm pressure. If each student loses 200 joules of heat in one second, calculate the rise in temperature noticedin 20 minutes ( Neglect loss of air to the outside as temperature is raised and C_(p) for air = ( 7)/( 2) R).

Answer» <html><body><p></p>Solution :Volume of room `= 10 m <a href="https://interviewquestions.tuteehub.com/tag/xx-747671" style="font-weight:bold;" target="_blank" title="Click to know more about XX">XX</a> 15m xx4m = 600m^(3)= 600 xx 10^(3) L =6 xx 10^(5) L`<br/> Molesof air in the room at `25^(@)<a href="https://interviewquestions.tuteehub.com/tag/c-7168" style="font-weight:bold;" target="_blank" title="Click to know more about C">C</a>` at 1 atm pressure <br/> `n = ( PV)/( RT) = ( 1 xx 6 xx 10^(5))/( 0.0821 xx 298) = 2.45 xx 10^(4)` <br/>Heat producedin1 sec by each student `= 200 J` <br/> `:. `Heat produced in 1 sec by 60 students `= 200 xx 60 J = 12000J` <br/> Heat produced in <a href="https://interviewquestions.tuteehub.com/tag/20-287209" style="font-weight:bold;" target="_blank" title="Click to know more about 20">20</a> minutes `=12000 xx 20 xx60 J = <a href="https://interviewquestions.tuteehub.com/tag/32-144-273643" style="font-weight:bold;" target="_blank" title="Click to know more about 144">144</a> xx 10^(5)J` <br/> Change in enthalpy of air, `<a href="https://interviewquestions.tuteehub.com/tag/delta-947703" style="font-weight:bold;" target="_blank" title="Click to know more about DELTA">DELTA</a> H = n C_(p) DeltaT` <br/>`:. 144 xx 10^(5) = ( 2.45 xx 10^(4)) = ( ( 7)/(2) xx 8.314)xx Delta T ` <br/>or ` Delta T = 20.2 K`</body></html>


Discussion

No Comment Found

Related InterviewSolutions