Answer:
2.03 Ω
Step-by-step explanation:
EMF: This can be defined as the potential difference of a cell when it is not delivering any current. The S.I unit of Emf is Volt.
The formula of emf is given as,
E = I(R+r)............................ Equation 1
Where E = Emf, I = current, R = External resistance, r = internal resistance.
Make r the subject of the equation
r = (E-IR)/I........................ Equation 2
Note: From ohm's law, V = IR.
r = (E-V)/I........................ Equation 3
Where V = Terminal voltage
Given: E = 24 V, I = 3.9 A, V = 16.1 V.
Substitute into equation 3
r = (24-16.1)/3.9
r = 7.9/3.9
r = 2.03 Ω