Answer:
r = 0.47 Ω
Explanation:
given,
voltage of the battery = 12 V
resistors are connected in parallel.
R₁ = 50 Ω and R₂ = 25 Ω
current,I = 0.70 A
Internal resistance = ?
equivalent resistance
[tex]R_{eq}= \dfrac{R_1R_2}{R_1+R_2}[/tex]
[tex]R_{eq}= \dfrac{50\times 25}{50+25}[/tex]
[tex]R_{eq}=16.67\ \Omega[/tex]
now,
[tex]\varepsilon = I (R_{eq}+r)[/tex]
r is the internal resistance
[tex]12 = 0.7\times (16.67+r)[/tex]
16.67 + r = 17.14
r = 0.47 Ω
Hence, internal resistance of the battery is equal to r = 0.47 Ω
