An industrial overhead door has a chain and sprocket system designed to reduce the force needed by an operator to open and close
1 answer:
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Answer:
proof in explanation
Explanation:
First, we will calculate the number of half-lives:
where,
n = no. of half-lives = ?
t = total time passed = 2100 million years
= half-life = 700 million years
Therefore,
Now, we will calculate the number of uranium nuclei left ():
and the rest of the uranium nuclei will become thorium nuclei ()
dividing both:
<u>Hence, it is proven that after 2100 million years there are seven times more thorium nuclei than uranium nuclei in the rock.</u>
Answer:
f = 1 m
Explanation:
The magnification of the lens is given by the formula:
where,
M = Magnification = 4
q = image distance = 5 m
p = object distance = ?
Therefore,
Now using thin lens formula:
<u>f = 1 m</u>