Which of the following ions forms a highly soluble hydroxide in water?

In carbon monoxide $(CO)$,how are the carbon and oxygen atoms bonded?

Two rain drops reach the earth with different terminal velocities having ratio $9:4$. Then the ratio of their volumes is

The number of turns in the primary and secondary coils of a transformer are $50$ and $200$ respectively. If the current in the primary coil is $4 ~A$,then the current in the secondary coil is: (in $~A$)

Two small drops of mercury,each of radius $R$,coalesce to form a single large drop. The ratio of the total surface energies before and after the change is

Two equal resistances when connected in series to a battery,consume electric power of $60 \ W$. If these resistances are now connected in parallel combination to the same battery,the electric power consumed will be............. $W$