Question

Two spacecraft are both 10 million kilometers from a star. The total power output of the star is 4 x 10²⁵ W. Spacecraft 1 has a solar panel with a radius of 18 m. Spacecraft 2 has a solar panel with a radius of 6 m. What is the ratio of the power collected by the solar panel of Spacecraft 1 to the power collected by the solar panel of Spacecraft 2.

Group of answer choices

a. 0.33

b. 0.06

c. 3

d. 1

e. 0.11

f. 9

g. 18

Answer 1

Power received by spacecraft 1, P1 = Ps x [R1²/4D²] ...(1)
Where Ps is the power emitted by the star, R1 is the radius of the solar panel of spacecraft 1 and D is the distance of the spacecraft from the star.

Similarly, power received by spacecraft 2,
P2 = Ps x [R2²/4D²] ...(1)
Where R2 is the radius of the solar panel in spacecraft 2.

(1) / (2) gives
P1/P2 = R1²/R2²
= (R1/R2)²
= (18/6)²
= 9