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The intensity of solar radiation reachin...

The intensity of solar radiation reaching the illuminated side of the Earth each second is `J = 1.36 kW//m^2`. Find the docrease in the internal energy and the muss of tho Sun per second. How long will it take for the Sun's mass to decrease due to radiation by `10%` ? The volume of the Sun is to be assumed to remain constant.

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The correct Answer is:
`3.8xx10^(26) W; 4.2 xx10^(9) kg//s; 1.5 xx10^(12) ` years `= 4.7 xx10^(9) s`
Multiplying the solar constant by the area of a sphere of radius equal to the astronomical unit, we obtain the total power of solar radiation `P= 4piJR^2` . The loss of mass per second in `mu=P//c^2` The Sun will lose ten percent of its mass in the time
`tau=(0.1M_(o.))/mu=(M_(o.)c^2)/(40piJR^2)`
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