Giana is looking up at a particular star in the night sky, and 2000 photons per second are entering her 7 mm diameter pupil due to the visible light emitted by the star. We make the approximation that the star only emits 565 nm photons. TJ lives on a faraway planet and happens to be looking up at the same star, and he measures the electric field of the light coming from the star to have amplitude 7.2 μN/C. If rG is Giana’s distance to the star, and if rT is Thanos’s distance to the star, then what is the ratio rG /rT ?

Giana is looking up at a particular star in the night sky, and 2000 photons per second are entering her 7 mm diameter pupil due to the visible light emitted by the star. We make the approximation that the star only emits 565 nm photons. TJ lives on a faraway planet and happens to be looking up at the same star, and he measures the electric field of the light coming from the star to have amplitude 7.2 μN/C. If rG is Giana’s distance to the star, and if rT is Thanos’s distance to the star, then what is the ratio rG /rT ?