AIIMS 2018 Physics Internal Resistance MCQ Question

To find the terminal voltage (V_t) of the battery, we use the formula $V_t = E - I \cdot r$, where $E$ is the emf (10 V), $I$ is the current (0.5 A), and $r$ is the internal resistance (3 Ω). Substituting the values gives $V_t = 10 V - (0.5 A \times 3 Ω) = 10 V - 1.5 V = 8.5 V$, which is not listed among the options, making option D correct.

Option A (10 V) is incorrect because it does not account for the voltage drop due to internal resistance. Option B (zero) is incorrect as the battery still provides a voltage when current flows. Option C (1.5 V) is also incorrect, as it misrepresents the voltage drop across the internal resistance rather than the terminal voltage.