3. For the circuit shown in the figure, what is the current through resistor R1, R2, R3? R3 (180 0) 10.0 V R2 15 V (60 0) R1 (340) 4. A Nichrome wire is 50 cm long. The resistivity of Nichrome is 1.5 x 10-60m at the 20 .C. The potential difference between the ends of wire is 4.0 V and a current of 2.0 A is flowing through the wire. A. Find the resistance of this wire. B. Calculate the diameter of the wire. C. If the wire is heated from 20 C to 70 C, calculate the new resistance of the wire that is produced by this change in the temperature (Temperature coefficient of resistivity a = 4 x 10-4 2) 2 a ) 4 = 252