Answer:
[tex]7.89\cdot 10^7 s = 78,900,000 s[/tex]
Explanation:
Let's analyze each option:
[tex]1.2\cdot 10^2 L[/tex]
We need to move the decimal point 2 places to the right, so
[tex]1.2\cdot 10^2 L=120 L[/tex]
So, 1200 L is wrong.
[tex]3.4\cdot 10^{-3} m[/tex]
We need to move the decimal point 3 places to the left, so
[tex]3.4\cdot 10^{-3} m = 0.0034 m[/tex]
so, 0.00034 m is wrong.
[tex]7.89\cdot 10^7 s[/tex]
We need to move the decimal point 7 places to the right, so
[tex]7.89\cdot 10^7 s = 78,900,000 s[/tex]
so, this choice is right.
[tex]5.00\cdot 10^{-5}g[/tex]
Moving the decimal point 5 places to the left,
[tex]5.00\cdot 10^{-5} g = 0.00005 g[/tex]
so, 0.00500 g is wrong.
