3. The circuit shown in Fig. 3 has two batteries of known emf's E and 2 and five resistors, whose resistances are measured in the known unit of resistance R: R = R = R and R3 = R4 = 3R and R5 = R/2. Internal resistances of the batteries and resistances of all connecting wires are negligible. Find electric currents I, 12, 13, 14 and 15 flowing through each respective resistor. How much power P is dissipated in the whole circuit in terms of emf's and R? R R5 E2 E1 RA Figure 3: Illustration for problem 3.