Question

Two bulbs with individual power ratings 1 W at 12 V and 2 W at 12 V are connected in parallel with a 12 V battery as shown. How much heat will be dissipated by respective bulbs in 10 seconds?

• A. $1J$, $2J$
• B. $2J$, $1J$
• C. $10J$, $20J$
• D. $20J$, $10J$

Answer 1

The correct option is C $10J$, $20J$

As the two bulbs are connected in parallel, the volatge across both the bulbs will be same and is 12 V in this case.

Heat dissipated by bulbs:
$H=VIt$
$=Pt$

Heat dissipated by $1W$ bulb is:
$H_1=1\times 10=10J$
Heat dissipated by $1W$ bulb is:
$H_2=2\times 10=20J$