Calculate:
(iii) the potential differences across R1 and R2 from the following circuit diagram​

Yup no bull frogs here man

The density of the block of iron is lees than the density of mercury but the density of the block of iron is greater than the density of water

Ican’t exactly answer this, but i can try to give a bit more info here.
astronomers are able to calculate a star’s life expectancy depending on its mass. (a larger star burns more gas, therefore having a shorter life span).
so astronomers can definitely predict the death of stars and the times they will die.
i hope this was in some way : )