Question

Please Answer this question of Physics

Question = 3 identical cells of EMF 4Volts are connected to a 6 Ohm resistance and internal resistance of r With a current of 1.5 Ampere. Find internal resistance and voltage
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Answer 1

${\sf{\underline{Answer}}}$ :

☛The internal resistance is 0.66 Ω

☛The Voltage is 3.01 Volts

${\sf{\underline{Step\: by \:Step \:Explanation }}}$

Given :

•E.M.F of cells = 4 V

•External Resistance R = 6 Ω.

•Current I = 1.5 A

We know that

=>I = $\frac{nE}{nr+R}$

$= > 1.5 = \frac{3 \times 4}{3r + 6} \\ \\ = > 1.5 = \frac{12}{3r + 6}$

Cross Multiply the terms :

=> 4.5r + 9 = 12

=> 4.5 r = 3

$= > r = \frac{30}{45} = 0.66$

•°• ${\bold{\underline{The\:internal\:resistance\:is\:0.66Ω}}}$

Using relation ,

${\bold{ V = E - Ir }}$

=>V = 4 - ( 1.5 × 0.66)

=>V = 3.01 Volts

•°• ${\bold{\underline{The\:potential\:difference \:is\:3.01\:Volts}}}$