Question

Consider two ohmic resistors denoted R1 and R2 which are connected in series with a

cell. Find the resistance and power of R2, given that the current flowing

through R1 and R2 is 0.25 A and that the voltage across the cell is 6 V. R1 = 1Ω.

Answer 1

The voltage across the combination is

$$V=V_1+V_2,\\ V=IR_1+IR_2,\\ IR_2=V-IR_1=6-0.25·1=5.75,\\\space\\ R_2=\frac{5.75}{0.25} =23\space\Omega.$$