List-I (Stage of Demographic Transition) | List-II (Country/Tribe) |
(A) High Fluctuating Stage | (I) Rainforest tribes |
(B) Early Expanding Stage | (II) Angola |
(C) Low Fluctuating Stage | (III) India |
(D) Late Expanding Stage | (IV) Japan |
A battery of emf \( E \) and internal resistance \( r \) is connected to a rheostat. When a current of 2A is drawn from the battery, the potential difference across the rheostat is 5V. The potential difference becomes 4V when a current of 4A is drawn from the battery. Calculate the value of \( E \) and \( r \).