Question

How long would it take a message sent as radio waves from earth to reach mars?

Answer 1

Answer:

$longest \: dstance \: btw \: earh - mars \\ (150 + 230) \times {10}^{6} km \\ t = \frac{d}{c} \\where \: c \: is \: the \: speed \: of \: light \\ = \frac{380 \times {10}^{6} km}{3 \times { {10}^{5} }km. {sec}^{ - 1} } \\ \\ when \: mars \: is \: close \: to \: earth \\ ( 230 - 150) \times {10}^{6} km \\ t = \frac{d}{c} \\where \: c \: is \: the \: speed \: of \: light \\ = \frac{80 \times {10}^{6} km}{3 \times { {10}^{5} }km. {sec}^{ - 1} }$