5. is b
but im not sure about 4
hope this helps
Answer:
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Answer:
43.89 min
Explanation:
Given that:-
The speed of light =
The distance =
The conversion of distance in km to distance into m is shown below as:-
1 km = 1000 m
So,
Distance =
The relation between speed distance and time is shown below as:-
Thus,
Time = 2633.33 seconds
Also, 1 s = 1/60 min
So,
Time=
Avogadro's number is defined as the number of elementary particles (molecules, atoms, compounds, etc.) per mole of a substance. It is equal to 6.022×1023 mol-1 and is expressed as the symbol NA.
It's 18 (the same as the number of protons:)