What happens when the filament of a bulb breaks?

Write the conventional symbol of the following component used in electric circuit diagram-

A wire joint

$15$ cells each of emf $2$ volt are connected in series but $2$ of them are connected wrongly. Calculate the emf of the combination.

In the given circuit diagram, identify the objects marked as $1, 2, 3$.

How can a continuous flow of current be obtained? What are the sources of energy and name of the devices required for continuous flow of current?

Write the conventional symbol of the following component used in electric circuit diagram-

Electric bulb

Write the conventional symbol of the following component used in electric circuit diagram-

An electric cell

Mention one similarity and one dissimilarity between electromotive force and potential difference. 

How much work is done in moving a charge of $2 \mathrm{C}$ across two points having a potential difference $10 \mathrm{V}$?