2. Solved Papers
  3. VMMC

VMMC VMMC Medical Solved Paper-2006

  • question_answer
    A body at a temperature of \[728{}^\circ C\] and has surface area \[5\,\,c{{m}^{2}},\] radiates 300 J of energy each minute. The emissivity is : (Given : Boltzmann constant \[=5.67\,\times {{10}^{-8}}\,W\,{{m}^{2}}{{K}^{4}}\])

    A) e = 0.18               

    B)        e = 0.02

    C)                        e = 0.2  

    D)        e = 0.15

    Correct Answer: A

    Solution :

    \[Q=EAt=e\sigma ({{T}^{4}}-T_{0}^{4})At\] where, t = time \[{{T}_{0}}=\]temperature of surrounding When,     \[T>{{T}_{0}}\]                 \[Q=e\,\sigma {{T}^{4}}\,At\] \[300=e\times (5.67\times {{10}^{-8}}){{(1000)}^{4}}(5.00\times {{10}^{-4}})(60)\] \[e=0.18\]


You need to login to perform this action.
You will be redirected in 3 sec spinner