Grade the bullbs in order of their brightness (All bubls are identical)

Explanation

As `iprop(1)/(R)`
`i_(1):i_(2)=(3)/(5R):(1)/(2R)=6:5`
`thereforei_(1)=(6i)/(11),i_(2)=(5i)/(11)`
`i_(3):i_(4)=(1)/(2R):(1)/(R)=1:2`
As `i_(3)+i_(4)=i_(1)`
`thereforei_(3)=(2i)/(11),i_(4)=(4i)/(11)`
power `=i^(2)R`
`therefore` Order of Brightness : `B_(5)gtB_(1)=B_(2)gtB_(6)gtB_(4)=B_(3)`