Answer: Stars are formed in clouds of gas and dust, known as nebulae. Nuclear reactions at the centre (or core) of stars provides enough energy to make them shine brightly for many years. The exact lifetime of a star depends very much on its size.
Explanation: I try to do your question, hope this help
It becomes a different element
Answer:
f=force m=mass and a=acceleration
You have to upload this in the area of mathematicians..!
Answer:
29.38 seconds
Explanation:
Half life, T = 22.07 s
No = 1293
Let N be the number of atoms left after time t
N = 1293 - 779 = 514
By the use of law of radioactivity

Where, λ is the decay constant
λ = 0.6931 / T = 0.6931 / 22.07 = 0.0314 decay per second
so,


take natural log on both the sides
0.9225 = 0.0314 t
t = 29.38 seconds