Question

How many bulbs of 81 should be joined in parallel to draw a current of 2A from a
battery of 4V?

Answer 1

4 bulbs of 81 should be joined

Answer 2

Explanation:

here is your answer

current ( i ) = 2 A

voltage ( v ) = 4 V

resistance ( r ) = ?

\begin{lgathered}r = \frac{v}{i} \\ r = \frac{4}{2} \\r = 2 \: ohm \\\end{lgathered}

r=

i

v

r=

2

4

r=2ohm

so the total resistance = 2ohm

assuming hte no. of bulbs be = x

now,

\begin{lgathered}\frac{1}{re} =x \times \frac{1}{r1} \\ \frac{1}{2} = x \times \frac{1}{8} \\ x = 4\end{lgathered}

re

1

=x×

r1

1

2

1

=x×

8

1

x=4

so it will required no. of bulb = 4

glad to help you

hope it helps

thank you.