Physics Unit33: Astrophysics and Cosmology (id: 935dad48e)

[单选题]
A star has absolute lu/k,bk er: jeuhda292 qmin; ugvry, 2gd5zosity equal to that of the Sun ($1.5 \times 10^{8} \; km$ from the Earth) but is 10 pc away from the Earth. By what factor will it appear dimmer than the Sun?

A. $2 \times 10^{-9}$
B. $2 \times 10^{-11}$
C. $2 \times 10^{-13}$
D. $2 \times 10^{-15}$


参考答案:  C


本题详细解析: 暂无