Answer:
E.M.F = 1.5 V
Explanation:
The equation relating EMF, internal resistance and external resistance is given by;
E = Ir + IR
Where; E is the EMF, I is the current, r is the internal resistance, and R is the external resistance.
Therefore;
When I = 0.6 A and R = 2Ω
E = 0.6 r + (0.6 × 2)
E = 0.6r + 1.2
When I = 0.2 A and R = 7 Ω
E = 0.2 r + (0.2 × 7)
E = 0.2 r + 1.4
Solving simultaneously;
E = 0.6r + 1.2
E = 0.2 r + 1.4 ; eliminating E
0 = 0.4 r - 0.2
0.4 r = 0.2
r = 0.5
Therefore;
E = 0.2(0.5) + 1.4
= 0.1 + 1.4
= 1.5 V
