Two $1\mathrm{.}50-$V batteries$$with their positive terminals

AMT

in the same direction$$are inserted in series into a

flashlight. One battery has an internal resistance of

$0\mathrm{.}255$ V$,$ and the other has an internal resistance of

$0\mathrm{.}153$ V$.$ When the switch is closed, the bulb carries a

current of $600$ mA$.($a$)$ What is the bulb$$s resistance?

$($b$)$ What fraction of the chemical energy transformed

appears as internal energy in the batteries