A radioactive element of mass 1g has half-life of 2 minutes, what fraction of the substance would have disintegrated after 10 minutes?
- 1/4
- 1/8
- 1/16
-
1/32
The correct answer is: D
Explanation
\(\frac{Original mass}{2^n}\) = Residual mass
Where n = number of activity = \(\frac{exposure time}{half life}\)
Given:
Original mass = 1g, exposure time = 10 minutes , half life = 2 minutes, Residual mass = ?
Substituting all the given parameters appropriately, we have
n = \(\frac{10}{2}\)
n = 5
\(\frac{Original mass}{2^n}\) = Residual mass
\(\frac{1}{2^5}\) = Residual mass
\(\frac{1}{32}\) = Residual mass
Residual mass = \(\frac{1}{32}\) or 0.03125g
There is an explanation video available .