1. If the same source as in question 1 (i.e., 10 W) is placed at the centre of a sphere 10.0 m in radius, what power is incident on a 10.0 X 10.0 cm square of the sphere?

Answer:
From part (b) I = 7.96X10-3 W/m2
Area = 0.10 X 0.10 = 0.010 m2
Power = IA = 7.96X10-3 (w/m2) X 0.010 m2
= 7.96X10-5 W

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