NEET Physics Nuclei Questions Solved


The sun radiates energy in all directions. The average radiations received on the earth surface from the sun is 1.4 kilowatt/m2.The average earth- sun distance is 1.5×1011 metres. The mass lost by the sun per day is
(1 day = 86400 seconds) 
(a) 4.4×109 kg          (b) 7.6×1014 kg
(c) 3.8×1012 kg         (d) 3.8×1014 kg

(d) Energy radiated = 1.4 kW/m2

=1.4 kJ/sec m2=1.4 kJ186400day m2=1.4×86400day m2

Total energy radiated/day 

=4π×1.5×10112×1.4×864001kJday=E

E=mc2m=Ec2

=4π×1.5×10112×1.4×864003×1082=3.8×1014 kg

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