In a system: Metabolic rate = M, work done by man = W, rate of convective, radiative and evaporative heat losses = Q and rate of heat storage = S. Then heat exchange between man and his environment is given by
Option (A)
M + W = Q + S
Option (B)
M – W = Q – S
M + W = Q – S
M – W = Q + S
Correct Option:
Question Solution:
A human body feels comfortable when the heat produced by metabolism of human body is equal to the sum of the heat dissipated to the surrounding and the heat stored in human body by raising the temperature body tissues. This phenomenon may be represented by the following equation.
QM - W = QE ± QR ± QC + QS
QM = Metabolic heat produced within the body.
W = Useful rate of working
QM-W = Heat to be dissipated to the atmosphere
QE = Heat lost by evaporative
QR = Heat lost or gained by radiation
QC = Heat lost or gained by convection and
QS = Heat stored in the body
(+) sign ® lost
(-) sign ® gain