Find out the equivalent resistance find out all the current's in every resistors
find out the voltage in resistor 1 and 4

1) 2.388ohms

2) R1 3.36A

R2 1.682A

R3 2.88A

R4 2.16A The current has 5.048A over all

3) Voltage in R1 is 3.36v

Voltage in R4 is 8.63v

Explanation:

1. Each of the resistance R1 and R2 are in parallel in series combination with R3 and R4 so we calculate

R1 and R2 which is 1×2÷(1+2)= 0.6667ohms

R3 and R4 which is 3×4÷( 3+4)= 1.71ohms

so the equivalent resistance is 0.667+ 1.71= *2.377ohms*

2. The overall current = voltage source ÷ total resistance

= 12÷ 2.377= 5.048Amps

so current in every resistor will be

current in 1ohms will be (2÷3)×5.048= 3.36Amps

current in 2ohms will be (1÷3)×5.048= 1.68Amps

current in 3ohms will be (4÷7)×5.048= 2.88amps

current in 4ohms will be (3÷7)× 5.048= 2.16amps

3. voltage in R1 is 0.667ohms × 5.048amps= 3.36v

voltage in R4 is 1.71ohms × 5.048amps= 8.63v

need to see circuit to get time constant