NEET AIPMT SOLVED PAPER SCREENING 2012

  • question_answer
    If the radius of a star is R and it acts as a black body, what would be the temperature of the star, in which the rate of energy production is Q? (\[\sigma \] stands for Stefan's constant.)

    A) \[Q/4\pi {{R}^{2}}\sigma \]         

    B)        \[{{(Q/4\pi {{R}^{2}}\sigma )}^{-1/2}}\]

    C)        \[{{(4\pi {{R}^{2}}Q/\sigma )}^{1/4}}\]

    D)        \[{{(Q/4\pi {{R}^{2}}\sigma )}^{1/4}}\]

    Correct Answer: D

    Solution :

    From Stefan' law, \[E=\sigma {{T}^{4}}\] So, the rate energy production                 \[Q=E\times A\]                 \[Q=\sigma {{T}^{4}}\times 4\pi {{R}^{2}}\] Temperature of star\[T={{\left( \frac{Q}{4\pi {{R}^{2}}\sigma } \right)}^{1/4}}\]


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