Question

plz answer guys
I need it quick plz do ​

Answer 1

4 bulbs of 81 should be joined.

Given :

Current (i) = 2 A

Voltage (v) = 4 V

Resistance (r) = ?

Let's find out the resistance first,

$\bigstar\;\boxed{ \sf R = \dfrac{V}{I}}$

$\implies \sf \: r = \dfrac{4}{2} = 2 \: ohm$

So,

We get,

Current (i) = 2 A.

Voltage (v) = 4 V.

Resistance (r) = 2 ohm.

now, let's consider the number of bulbs as - x

$\sf \implies \dfrac{1}{re} =x \times \dfrac{1}{r1}$

$\sf \implies \dfrac{1}{2} = x \times \dfrac{1}{8}$

$\sf \implies \: x = 4$

Hence,

4 bulbs of 81 should be joined.