Answer:R=7.12ohms
Explanation:
Emf (electromotive force) is the source of energy in an electric circuit. It is also the sum of all potential drops across loads in an electric circuit.
Resistance is the opposition to the flow of current in an electric circuit. The presence of a load therefore tends to restrict the current flowing through it.
According to ohm's law, E=IR
E is the emf
I is the current
R is effective resistance (load can be connected in series or parallel)
According to the question, Emf = 1.50V, current(I) =0.17A and terminal voltage V =1.40V
First we need to get the internal resistance (r), from the formula
Terminal voltage V = E -Ir where r is the internal resistance
Substituting
1.40=1.50-0.17r
1.40-1.50=-0.17r
-0.1=-0.17r
r=-0.17/-0.1
r= 1.7ohms
To get R, using E=I(R+r) since the load is in series with internal resistance,we add both to get our effective resistance
1.50=0.17(R+1.7)
1.50=0.17R+0.289
1.50-0.289=0.17R
1.211=0.17R
R=1.211/0.17
R=7.12ohms.
