The only one on the list that I know is radioactive is Carbon-14.
Answer:
Explanation:
Object is Floating in a liquid
weight of object is equal to weight of displaced fluid
i.e.

i.e.
where V and V' is the volume of object and volume of object inside the liquid.
therefore mass of liquid displaced must be equal to mass of object
Answer:
d' = 75.1 cm
Explanation:
It is given that,
The actual depth of a shallow pool is, d = 1 m
We need to find the apparent depth of the water in the pool. Let it is equal to d'.
We know that the refractive index is also defined as the ratio of real depth to the apparent depth. Let the refractive index of water is 1.33. So,

or
d' = 75.1 cm
So, the apparent depth is 75.1 cm.
if there is not a reaction