An astronaut with mass 84kg is at rest in space, before firing her water pack to move toward the shuttle. If the amount of water
1 answer:
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Answer:
Thus the time taken is calculated as 387.69 years
Solution:
As per the question:
Half life of = 28.5 yrs
Now,
To calculate the time, t in which the 99.99% of the release in the reactor:
By using the formula:
where
N = No. of nuclei left after time t
= No. of nuclei initially started with
(Since, 100% - 99.99% = 0.01%)
Thus
Taking log on both the sides:
t = 387.69 yrs
Answer:
Minimum number of photons required is 1.35 x 10⁵
Explanation:
Given:
Wavelength of the light, λ = 850 nm = 850 x 10⁻⁹ m
Energy of one photon is given by the relation :
....(1)
Here h is Planck's constant and c is speed of light.
Let N be the minimum number of photons needed for triggering receptor.
Minimum energy required for triggering receptor, E₁ = 3.15 x 10⁻¹⁴ J
According to the problem, energy of N number of photons is equal to the energy required for triggering, that is,
E₁ = N x E
Put equation (1) in the above equation.
Substitute 3.15 x 10⁻¹⁴ J for E₁, 850 x 10⁻⁹ m for λ, 6.6 x 10⁻³⁴ J s for h and 3 x 10⁸ m/s for c in the above equation.
N = 1.35 x 10⁵