The EMF of the battery is 3.7 volts. Internal resistance 1.5 ohm. External resistance 11.7 ohm. Determine voltage

EMF = 3.7 V.

r = 1.5 ohms.

R = 11.7 ohms.

U -?

According to Ohm’s law for a closed loop, the current I in the circuit is directly proportional to the electromotive force of the EMF current source and is inversely proportional to the sum of the external R and internal resistance r: I = EMF / (R + r).

Let’s write Ohm’s law for a section of the circuit: I = U / R, where U is the voltage at the terminals of the current source.

EMF / (R + r) = U / R.

U = EMF * R / (R + r).

U = 3.7V * 11.7Ω / (11.7Ω + 1.5Ω) = 3.3V.

Answer: the voltage at the poles of the battery is U = 3.3 V.