When arranging the copper mines of Rajasthan from north to south, the correct order is:
- Khetri (ii), located in the northern part of Rajasthan, is the first.
- Alwar (iv) comes next, located south of Khetri.
- Bhilwara (i) is further south, located in the southern part of the state.
- Udaipur (iii) is located at the southernmost position among the listed cities.
Thus, the correct order is: Khetri (ii), Alwar (iv), Bhilwara (i), and Udaipur (iii).
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 \( r \).