An electric source has an emf of 130 V and a terminal voltage of 110 V. If it supplies a terminal current of 20 A, its internal resistance will be
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → \( 1\,\Omega \)
While a source supplies current, its terminal voltage is less than the emf by the drop across the internal resistance.
\( \displaystyle V = E - I r \;\Rightarrow\; r = \frac{E - V}{I} \)
\( \displaystyle r = \frac{130 - 110}{20} = \frac{20}{20} = 1\,\Omega \)