You are Tanya/Tanmay of 58, S.K. Nagar, A.K. Town, Veershahar. Write a letter to the editor of a national daily expressing your concern over the issue and stressing the importance of teaching children how to deal with cyberbullying.


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 \( r \).