Physics

Find the value of current I drawn from the cell.
(a) Calculate the current I.
(b) Calculate the terminal voltage.

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(a) As, the two 15Ω resistors are in series

So, R_s = 15 + 15 = 30Ω

Now, R_s (i.e., 30Ω) and 30Ω are in parallel,

$\therefore \dfrac{1}{\text{R}_p} = \dfrac{1}{30} + \dfrac{1}{30} \\[1em] = \dfrac{2}{30} \\[1em] = \dfrac{1}{15}$

∴ R_p = 15Ω

Now, total resistance of the circuit = 2Ω + 15Ω = 17Ω

$\text{I} = \dfrac{\text{emf}}{\text{total resistance}} \\[1em] = \dfrac{3.4}{17} \\[1em] = 0.2 \text{ A}$

∴ Current I = 0.2 A

(b) Terminal voltage [V] = emf - Ir
= 3.4 - [0.2 x 2] = 3.4 - 0.4
= 3 V

Hence, terminal voltage = 3 V

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