Question

2) The coefficient of absorption and coefficient of transmission are 0.50 and 0.25 respectively. If 200
calories of radiant heat is incident on the surface of the body, the quantity of heat reflected will be
b) 150 cal
a) 140 cal
d) 50 cal
c) 200 cal​

Answer 1

Answer :
      The quantity of Heat Reflected is 50 calories
Step-by-step Explanation :
   Given : Coefficient of absorption (a) = 0.50
                Coefficient of transmission (t) = 0.25
                 Heat Incident (Q) = 200 calories
  To find : The quantity of Heat Reflected (Qr) = ?
We know that,
       a + r + t = 1
Where ,
           a = Coefficient of absorption,
            r = Coefficient of Reflection ,
            t = Coefficient of transmission
Substituting the given value in above formula we get ,
       0.50 + r + 0.25 = 1
          r + 0.75 = 1
           r = 1 - 0.75
           r = 0.25
Also,
     Qr = Q × r
Where ,
         Qr = Heat Reflected.
          Q = Heat Incident,
           r = Coefficient of Reflection
Substituting the given value in above formula we get,
       Qr = 200 × 0.25
            = 50 calories
Hence the quantity of Heat Reflected is 50 calories .