A 12 V battery is rated for an internal resistance of 0.50
PHYSICS · Single correct · CBSE · Physics · Current Electricity · Current Electricity
Problem
A 12 V battery is rated for an internal resistance of 0.50 Ω. When a high-current appliance is connected, the terminal voltage measured across the battery drops to 10 V. Which statement best explains this observation?
(a) The large current quickly depletes charge at the electrodes faster than chemical reactions can replace it, so the electrode potential temporarily falls to about 10 V.
(b) Current through the battery causes an internal voltage drop equal to Ir, reducing the terminal voltage below the emf.
(c) Because the battery’s emf obeys E=Ir, the 4 A current lowers the emf itself from 12 V to about 10 V.
(d) Because the appliance has a very large resistance, most of the 12 V drops across it, leaving only 10 V to appear at the battery terminals.