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प्रश्न
What is perfectly black body ? Explain Ferry’s black body.
उत्तर
A perfectly black body which absorbs all the energy incident on it. The coefficient of absorption of lamp black is 98%.
(i) It consist of double walled hollow metal sphere having small aperture.
(ii) Inner surface is coated with lamp black.
(iii) Outer surface is Nickel polished.
(iv) The space between sphere is evacuated.
(v) The radiant energy entering suffers multiple reflection and get 98% absorbed at each reflection.
(vi) Thus the aperture acts as perfectly black body.
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संबंधित प्रश्न
Draw a neat labelled diagram for Ferry's perfectly black body.
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(a) both p and E increase
(b) p increases and E decreases
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(d) both p and E decrease.
Show graphical representation of energy distribution spectrum of perfectly black body.
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(A) from 4000 Å to 7000 Å
(B) from 7700 Å to 4 x 106 Å
(C) from 106 Å to 108 Å
(D) from 4 x 10-12 Å to 4 x 108 Å
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