Question

An electric bulb is rated as 10W , 220V.How many of these bulbs can be connected in parallel across the two wires of 220V supply line if the maximum current which can be drawn is 5A?

Answer 1

A parallel circuit contains junctions and so there is more than one path for the current.  

At the point where the circuit have branches, the flow of current gets seperated and it rejoins so that it completes the circuit.  

                        $R =\frac {V^2} {P}\\=\frac{(220)^2}{10}\\=4840$

                        $R_{eq}=\frac {V} I\\=\frac {220 }{ 5}\\= 44$

                        $\frac {1} {R_eq} \\= \frac {n}{R}$$n = \frac {R } { R_eq} \\= \frac {4840} {44} \\=110$

Answer 2

Answer:

$\begin{lgathered}R =\frac {V^2} {P}\\=\frac{(220)^2}{10}\\=4840\end{lgathered} </p><p></p><p>                        \begin{lgathered}R_{eq}=\frac {V} I\\=\frac {220 }{ 5}\\= 44\end{lgathered} </p><p></p><p>                        \begin{lgathered}\frac {1} {R_eq} \\= \frac {n}{R}\end{lgathered} \begin{lgathered}n = \frac {R } { R_eq} \\= \frac {4840} {44} \\=110\end{lgathered} </p><p></p><p>$