A spring balance reads `10kg` when a bucket of water is suspened from it . What will be the reading of the balance when an iron piece of mass `7.2 kg` suspended by a string is immersed with half its volume inside the water in the bucket? Relative density of iron is `7.2`

Options

A. `10kg`
B. `10.5 kg`
C. `13.6kg`
D. `17.2kg`

Answer

B

Explanation

Reading =weight of bucket of water+magnitude of upthrust on block
`=(10g)+1/2((7.2)/(7.2 rho_(w)))rho_(w)g`.
`=10.5g=10.5kg`.