Physics

It takes time 8 min for light to reach from the sun to the earth surface. If speed of light is taken to be $$ 3 \times 10^{8} ms^{-1}$$, find the distance from the sun to the earth in km.


SOLUTION
Given:
Time = 8 min
Speed = $$ 3 \times 10^{8} ms^{-1}$$

Time is not given in the standard from, i.e., in seconds. 
So first convert to seconds;
$$1 min$$ = $$60s$$
$$8 min$$ = $$8$$ $$\times$$ $$60s = 480s$$
Distance  $$=s$$ $$\times$$ $$t$$
=  $$ 3 \times 10^{8} \times 480$$
$$ = 1.44 \times 10^{8} km$$
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