Question

A battery has an emf of 15 V and internal resistance of 1 Ω. If the terminal to terminal potential difference less than equal to or greater than 15 V if the current in the battery is (1) from negative to positive terminal, (2) from positive to negative terminal, (3) zero current ?

• A. Less, greater, equal
• B. Less, less, equal
• C. Greater, greater, equal
• D. Greater, less, equal

Answer 1

Answer: (A)

Less, greater, equal

Answer 2

(i) If current in battery is from –ve to +ve

⇒  battery discharging ⇒ V = E – Ir

⇒ V < E ⇒ V < 15 volt

(ii) Battery charging

⇒ V = E + Ir

⇒ V > 15 volt

(iii) Zero current

⇒ V = E = 15 volt