Questions on EMF and internal resistance

Q1.

A battery is connected to a 10 resistor as shown. The e.m.f. (electromotive force) of the battery is 12V.

(a)

(i) Explain what is meant by the e.m.f. of a battery.

(ii) When the switch is open the voltmeter reads 12.0V and when it is closed it reads 11.5 V. Explain why the readings are different.

(3)

(b) Calculate the internal resistance of the battery.

(3)
(Total 6 mark)