An arrangement designed to measure the emf E and internal resistance r of a battery is depicted in the figure. The voltmeter possesses a very high resistance, whereas the ammeter has some resistance. While the switch S is open, the voltmeter indicates 1.52 V . Once the switch is closed, the voltmeter's reading decreases to 1.45 V and the ammeter displays 1.0 A . Calculate the emf and the internal resistance of the ba

Step-by-step solution

When the switch S is open, the current in the circuit is zero. The voltmeter measures the emf of the battery. E = 1.52 V When the switch S is closed, a current I = 1.0 A flows through the circuit. The voltmeter measures the terminal voltage V across the battery. The terminal voltage is given by: V = E - Ir Substituting the given values: 1.45 = 1.52 - (1.0)r r = 1.52 - 1.45 = 0.07 The emf is 1.52 V and the internal resistance is 0.07 .