Final answer:
In a series circuit, the total voltage and resistance can be calculated by summing the individual values. In a parallel circuit, the equivalent resistance can be calculated using inverse addition. The current in each branch can be determined using Ohm's law and Kirchhoff's laws.
Step-by-step explanation:
In a series circuit, the total voltage E1 is equal to the sum of the individual voltages. The voltage drops across resistors E2-3 and E5-6-7 are determined by Ohm's law: V = IR. The total resistance RT is the sum of the individual resistances. The resistances R1, R2-3, R4, and R5-6-7 can be calculated using the given values.
In a parallel circuit, the equivalent resistance Req for two resistors is calculated using the formula 1/Req = 1/R1 + 1/R2. Similarly, the equivalent resistance Req for three resistors is calculated using the formula 1/Req = 1/R1 + 1/R2 + 1/R3. The total voltage ET is the same across all the resistors in parallel. The total current IT is the sum of the individual currents. The currents I2, I3, I5, I6, and I7 can be calculated using Ohm's law and Kirchhoff's laws.