#4.3.2a
source of e.m.f.; internal resistance
#4.3.2b
terminal p.d.; 'lost volts'
#4.3.2c
(i) the equations \(ε = I(R + r) \) and \(ε = V + Ir \) (ii) techniques and procedures used to determine the internal resistance of a chemical cell or other source of e.m.f. PAG4